diff --git a/DESCRIPTION b/DESCRIPTION
index b61d269..1a729de 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: GDPuc
 Title: Easily Convert GDP Data
-Version: 0.11.1
+Version: 1.0.0
 Date: 2023-07-13
 Authors@R:
     person("Johannes", "Koch", , "jokoch@pik-potsdam.de", role = c("aut", "cre"))
@@ -42,4 +42,4 @@ VignetteBuilder:
 Config/testthat/edition: 3
 Encoding: UTF-8
 Roxygen: list(markdown = TRUE)
-RoxygenNote: 7.2.3
+RoxygenNote: 7.3.1
diff --git a/NAMESPACE b/NAMESPACE
index f2a3393..edff7de 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -1,6 +1,8 @@
 # Generated by roxygen2: do not edit by hand
 
+export(convertCPI)
 export(convertGDP)
+export(convertSingle)
 export(print_source_info)
 importFrom(magrittr,"%>%")
 importFrom(rlang,"!!")
diff --git a/R/adapt_source.R b/R/adapt_source.R
index 6b1f4b8..c316049 100644
--- a/R/adapt_source.R
+++ b/R/adapt_source.R
@@ -1,3 +1,20 @@
+adapt_source_USA <- function(gdp, source, replace_NAs) {
+  source_USA <- source %>%
+    dplyr::filter(.data$iso3c == "USA") %>%
+    dplyr::select("year", "USA_deflator" = "GDP deflator")
+
+  source_adapted <- source %>%
+    dplyr::left_join(source_USA, by = dplyr::join_by("year")) %>%
+    dplyr::mutate("GDP deflator" = .data$USA_deflator)
+
+  if (!is.null(replace_NAs) && replace_NAs[1] == "with_USA") {
+    source_USA <- source %>% dplyr::filter(.data$iso3c == "USA")
+    source_adapted <- purrr::map(unique(gdp$iso3c), ~dplyr::mutate(source_USA, "iso3c" = .x)) %>%
+      purrr::list_rbind()
+  }
+  source_adapted
+}
+
 #
 adapt_source <- function(gdp, source, with_regions, replace_NAs) {
   rlang::check_installed(c("zoo"), reason = "in order for 'replace_NAs' to work.")
diff --git a/R/check_user_input.R b/R/check_user_input.R
index 9c1a6d6..1afc909 100644
--- a/R/check_user_input.R
+++ b/R/check_user_input.R
@@ -2,21 +2,23 @@
 #
 # check_user_input performs some checks on the function arguments.
 # @return TRUE or an Error
-check_user_input <- function(gdp, unit_in, unit_out, source, with_regions, replace_NAs, verbose, return_cfs) {
+check_user_input <- function(gdp,
+                             unit_in,
+                             unit_out,
+                             source,
+                             use_USA_deflator_for_all,
+                             with_regions,
+                             replace_NAs,
+                             verbose,
+                             return_cfs) {
 
-  # Check the gdp argument
   check_gdp(gdp)
-  # Check the unit_in and unit_out arguments
   check_unit_in_out(unit_in, unit_out)
-  # Check the source argument
   source <- check_source(source)
-  # Check the with_regions argument. Depends on unit_in, unit_out, and the source tibble
+  check_use_USA_deflator_for_all(use_USA_deflator_for_all, unit_in, unit_out)
   check_with_regions(unit_in, unit_out, source, with_regions)
-  # Check the replaceNAs argument. Depends on the with_regions argument.
   check_replace_NAs(with_regions, replace_NAs)
-  # Check the verbose argument
   check_verbose(verbose)
-  # Check the return_cfs argument
   check_return_cfs(return_cfs)
 
   TRUE
@@ -59,6 +61,7 @@ check_unit_in_out <- function(unit_in, unit_out) {
     "current Int\\$PPP",
     "constant .... LCU",
     "constant .... US\\$MER",
+    "constant .... \u20ac",
     "constant .... Int\\$PPP"
   )
   if (!is.character(unit_in) || !any(sapply(valid_units, grepl, unit_in))) {
@@ -95,9 +98,22 @@ check_source <- function(source) {
   if (!all(required_cols_in_source %in% colnames(source))) {
     abort("Invalid 'source' argument. Required columns are: {paste(required_cols_in_source, collapse = '; ')}")
   }
+  if (nrow(dplyr::distinct(source)) != nrow(dplyr::distinct(source, .data$iso3c , .data$year))) {
+    abort("Invalid 'source' argument. Duplicate iso3c - year pairs found.")
+  }
   source
 }
 
+# Check input parameter 'verbose'
+check_use_USA_deflator_for_all <- function(use_USA_deflator_for_all, unit_in, unit_out) {
+  if (!is.logical(use_USA_deflator_for_all)) {
+    abort("Invalid 'use_USA_deflator_for_all' argument. Has to be either TRUE or FALSE.")
+  }
+  if (use_USA_deflator_for_all && any(grepl("current", c(unit_in, unit_out)))) {
+    abort("Setting 'use_USA_deflator_for_all' to TRUE should only be applied between conversion of constant units.")
+  }
+}
+
 # Check input parameter 'with_regions'
 check_with_regions <- function(unit_in, unit_out, source, with_regions) {
   if (!is.null(with_regions)) {
@@ -129,9 +145,9 @@ check_replace_NAs <- function(with_regions, replace_NAs) {
         "convertGDP(replace_NAs = '\"linear_regional_average\" has been replaced by c(\"linear\", \"regional_average\")')"
       )
     }
-    if (!all(replace_NAs %in% c(NA, 0, 1, "no_conversion", "linear", "regional_average"))) {
-      abort("Invalid 'replace_NAs' argument. Has to be either NULL, NA, 0, 1, no_conversion, linear, regional_average or \\
-            a combination of the above.")
+    if (!all(replace_NAs %in% c(NA, 0, 1, "no_conversion", "linear", "regional_average", "with_USA"))) {
+      abort("Invalid 'replace_NAs' argument. Has to be either NULL, NA, 0, 1, no_conversion, linear, \\
+            regional_average, with_USA or a combination of the above.")
     }
     if (length(replace_NAs) > 1 && replace_NAs[1] != "linear") {
       abort("Invalid 'replace_NAs' argument. The only accepted combinations of arguments start with 'linear', e.g. \\
diff --git a/R/composite_conversions.R b/R/composite_conversions.R
index b7f4909..ecd8b0b 100644
--- a/R/composite_conversions.R
+++ b/R/composite_conversions.R
@@ -6,17 +6,24 @@
 # Convert from current LCU to constant Int$PPP base y
 current_LCU_2_constant_IntPPP_base_y <- function(gdp, base_y, source) {
   gdp %>%
-    current_LCU_2_constant_LCU_base_y(base_y, source) %>%
+    current_LCU_2_constant_LCU_base_y(base_y, source) %>e%
     constant_LCU_2_constant_IntPPP(base_y, source)
 }
 
 # Convert from current LCU to constant US$MER base y
 current_LCU_2_constant_USMER_base_y <- function(gdp, base_y, source) {
   gdp %>%
-    current_LCU_2_constant_LCU_base_y(base_y, source) %>%
+    current_LCU_2_constant_LCU_base_y(base_y, source) %>e%
     constant_LCU_2_constant_USMER(base = base_y, source)
 }
 
+# Convert from current LCU to constant € base y
+current_LCU_2_constant_EURO_base_y <- function(gdp, base_y, source) {
+  gdp %>%
+    current_LCU_2_constant_USMER_base_y(base_y, source) %>e%
+    constant_USMER_2_constant_EURO(base = base_y, source)
+}
+
 #------------------------------------------------------------
 #------------------------------------------------------------
 #------------------------------------------------------------
@@ -25,30 +32,28 @@ current_LCU_2_constant_USMER_base_y <- function(gdp, base_y, source) {
 # Convert from current Int$PPP to current US$MER
 current_IntPPP_2_current_USMER <- function(gdp, source) {
   gdp %>%
-    current_IntPPP_2_current_LCU(source) %>%
+    current_IntPPP_2_current_LCU(source) %>e%
     current_LCU_2_current_USMER(source)
 }
 
 # Convert from current Int$PPP to constant LCU base y
 current_IntPPP_2_constant_LCU_base_y <- function(gdp, base_y, source) {
   gdp %>%
-    current_IntPPP_2_current_LCU(source) %>%
+    current_IntPPP_2_current_LCU(source) %>e%
     current_LCU_2_constant_LCU_base_y(base_y, source)
 }
 
 # Convert from current Int$PPP to constant Int$PPP base y
 current_IntPPP_2_constant_IntPPP_base_y <- function(gdp, base_y, source) {
   gdp %>%
-    current_IntPPP_2_current_LCU(source) %>%
-    current_LCU_2_constant_LCU_base_y(base_y, source) %>%
+    current_IntPPP_2_constant_LCU_base_y(base_y, source) %>e%
     constant_LCU_2_constant_IntPPP(base = base_y, source)
 }
 
 # Convert from current Int$PPP to constant US$MER base y
 current_IntPPP_2_constant_USMER_base_y <- function(gdp, base_y, source) {
   gdp %>%
-    current_IntPPP_2_current_LCU(source) %>%
-    current_LCU_2_constant_LCU_base_y(base_y, source) %>%
+    current_IntPPP_2_constant_LCU_base_y(base_y, source) %>e%
     constant_LCU_2_constant_USMER(base = base_y, source)
 }
 
@@ -60,32 +65,38 @@ current_IntPPP_2_constant_USMER_base_y <- function(gdp, base_y, source) {
 # Convert from current US$MER to current Int$PPP
 current_USMER_2_current_IntPPP <- function(gdp, source) {
   gdp %>%
-    current_USMER_2_current_LCU(source) %>%
+    current_USMER_2_current_LCU(source) %>e%
     current_LCU_2_current_IntPPP(source)
 }
 
 # Convert from current US$MER to constant LCU base y
 current_USMER_2_constant_LCU_base_y <- function(gdp, base_y, source) {
   gdp %>%
-    current_USMER_2_current_LCU(source) %>%
+    current_USMER_2_current_LCU(source) %>e%
     current_LCU_2_constant_LCU_base_y(base_y, source)
 }
 
 # Convert from current US$MER to constant US$MER base y
 current_USMER_2_constant_USMER_base_y <- function(gdp, base_y, source) {
   gdp %>%
-    current_USMER_2_constant_LCU_base_y(base_y, source) %>%
+    current_USMER_2_constant_LCU_base_y(base_y, source) %>e%
     constant_LCU_2_constant_USMER(base = base_y, source)
 }
 
 # Convert from current US$MER to constant Int$PPP base y
 current_USMER_2_constant_IntPPP_base_y <- function(gdp, base_y, source) {
   gdp %>%
-    current_USMER_2_current_LCU(source) %>%
-    current_LCU_2_constant_LCU_base_y(base_y, source) %>%
+    current_USMER_2_constant_LCU_base_y(base_y, source) %>e%
     constant_LCU_2_constant_IntPPP(base = base_y, source)
 }
 
+# Convert from current US$MER to constant € base y
+current_USMER_2_constant_EURO_base_y <- function(gdp, base_y, source) {
+  gdp %>%
+    current_USMER_2_constant_USMER_base_y(base_y, source) %>e%
+    constant_USMER_2_constant_EURO(base = base_y, source)
+}
+
 #------------------------------------------------------------
 #------------------------------------------------------------
 #------------------------------------------------------------
@@ -94,21 +105,21 @@ current_USMER_2_constant_IntPPP_base_y <- function(gdp, base_y, source) {
 # Convert from constant LCU base x to current Int$PPP
 constant_LCU_base_x_2_current_IntPPP <- function(gdp, base_x, source) {
   gdp %>%
-    constant_LCU_base_x_2_current_LCU(base_x, source) %>%
+    constant_LCU_base_x_2_current_LCU(base_x, source) %>e%
     current_LCU_2_current_IntPPP(source)
 }
 
 # Convert from constant LCU base x to current Int$PPP
 constant_LCU_base_x_2_current_USMER <- function(gdp, base_x, source) {
   gdp %>%
-    constant_LCU_base_x_2_current_LCU(base_x, source) %>%
+    constant_LCU_base_x_2_current_LCU(base_x, source) %>e%
     current_LCU_2_current_USMER(source)
 }
 
 # Convert from constant LCU in one base year to constant Int$PPP of another
 constant_LCU_base_x_2_constant_IntPPP_base_y <- function(gdp, base_x, base_y, source) {
   gdp %>%
-    constant_LCU_base_x_2_constant_LCU_base_y(base_x, base_y, source) %>%
+    constant_LCU_base_x_2_constant_LCU_base_y(base_x, base_y, source) %>e%
     constant_LCU_2_constant_IntPPP(base = base_y, source)
 }
 
@@ -116,10 +127,17 @@ constant_LCU_base_x_2_constant_IntPPP_base_y <- function(gdp, base_x, base_y, so
 # Convert from constant LCU in one base year to constant US$MER of another
 constant_LCU_base_x_2_constant_USMER_base_y <- function(gdp, base_x, base_y, source) {
   gdp %>%
-    constant_LCU_base_x_2_constant_LCU_base_y(base_x, base_y, source) %>%
+    constant_LCU_base_x_2_constant_LCU_base_y(base_x, base_y, source) %>e%
     constant_LCU_2_constant_USMER(base = base_y, source)
 }
 
+# Convert from constant LCU in one base year to constant € of another
+constant_LCU_base_x_2_constant_EURO_base_y <- function(gdp, base_x, base_y, source) {
+  gdp %>%
+    constant_LCU_base_x_2_constant_USMER_base_y(base_x, base_y, source) %>e%
+    constant_USMER_2_constant_EURO(base = base_y, source)
+}
+
 #------------------------------------------------------------
 #------------------------------------------------------------
 #------------------------------------------------------------
@@ -128,49 +146,52 @@ constant_LCU_base_x_2_constant_USMER_base_y <- function(gdp, base_x, base_y, sou
 # Convert from constant Int$PPP base year x to current LCU
 constant_IntPPP_base_x_2_current_LCU <- function(gdp, base_x, source) {
   gdp %>%
-    constant_IntPPP_2_constant_LCU(base = base_x, source) %>%
+    constant_IntPPP_2_constant_LCU(base = base_x, source) %>e%
     constant_LCU_base_x_2_current_LCU(base_x, source)
 }
 
 # Convert from constant Int$PPP base year x to current US$MER
 constant_IntPPP_base_x_2_current_USMER <- function(gdp, base_x, source) {
   gdp %>%
-    constant_IntPPP_2_constant_LCU(base = base_x, source) %>%
-    constant_LCU_base_x_2_current_LCU(base_x, source) %>%
+    constant_IntPPP_base_x_2_current_LCU(base_x, source) %>e%
     current_LCU_2_current_USMER(source)
 }
 
 # Convert from constant Int$PPP base year x to current Int$PPP
 constant_IntPPP_base_x_2_current_IntPPP <- function(gdp, base_x, source) {
   gdp %>%
-    constant_IntPPP_2_constant_LCU(base = base_x, source) %>%
-    constant_LCU_base_x_2_current_LCU(base_x, source) %>%
+    constant_IntPPP_base_x_2_current_LCU(base_x, source) %>e%
     current_LCU_2_current_IntPPP(source)
 }
 
 # Convert from constant Int$PPP in one base year to constant LCU of another
 constant_IntPPP_base_x_2_constant_LCU_base_y <- function(gdp, base_x, base_y, source) {
   gdp %>%
-    constant_IntPPP_2_constant_LCU(base = base_x, source) %>%
+    constant_IntPPP_2_constant_LCU(base = base_x, source) %>e%
     constant_LCU_base_x_2_constant_LCU_base_y(base_x, base_y, source)
 }
 
 # Convert constant Int$PPP series from one base year to another
 constant_IntPPP_base_x_2_constant_IntPPP_base_y <- function(gdp, base_x, base_y, source) {
   gdp %>%
-    constant_IntPPP_2_constant_LCU(base = base_x, source) %>%
-    constant_LCU_base_x_2_constant_LCU_base_y(base_x, base_y, source) %>%
+    constant_IntPPP_base_x_2_constant_LCU_base_y(base_x, base_y, source) %>e%
     constant_LCU_2_constant_IntPPP(base = base_y, source)
 }
 
 # Convert from constant Int$PPP in one base year to constant US$MER of another
 constant_IntPPP_base_x_2_constant_USMER_base_y <- function(gdp, base_x, base_y, source) {
   gdp %>%
-    constant_IntPPP_2_constant_LCU(base = base_x, source) %>%
-    constant_LCU_base_x_2_constant_LCU_base_y(base_x, base_y, source) %>%
+    constant_IntPPP_base_x_2_constant_LCU_base_y(base_x, base_y, source) %>e%
     constant_LCU_2_constant_USMER(base = base_y, source)
 }
 
+# Convert from constant Int$PPP in one base year to constant € of another
+constant_IntPPP_base_x_2_constant_EURO_base_y <- function(gdp, base_x, base_y, source) {
+  gdp %>%
+    constant_IntPPP_base_x_2_constant_USMER_base_y(base_x, base_y, source) %>e%
+    constant_USMER_2_constant_EURO(base = base_y, source)
+}
+
 #------------------------------------------------------------
 #------------------------------------------------------------
 #------------------------------------------------------------
@@ -179,47 +200,102 @@ constant_IntPPP_base_x_2_constant_USMER_base_y <- function(gdp, base_x, base_y,
 # Convert from constant US$MER base year x to current LCU
 constant_USMER_base_x_2_current_LCU <- function(gdp, base_x, source) {
   gdp %>%
-    constant_USMER_2_constant_LCU(base = base_x, source) %>%
+    constant_USMER_2_constant_LCU(base = base_x, source) %>e%
     constant_LCU_base_x_2_current_LCU(base_x, source)
 }
 
 # Convert from constant US$MER base year x to current Int$PPP
 constant_USMER_base_x_2_current_IntPPP <- function(gdp, base_x, source) {
   gdp %>%
-    constant_USMER_2_constant_LCU(base = base_x, source) %>%
-    constant_LCU_base_x_2_current_LCU(base_x, source) %>%
+    constant_USMER_base_x_2_current_LCU(base_x, source) %>e%
     current_LCU_2_current_IntPPP(source)
 }
 
 # Convert from constant US$MER base year x to current US$MER
 constant_USMER_base_x_2_current_USMER <- function(gdp, base_x, source) {
   gdp %>%
-    constant_USMER_2_constant_LCU(base = base_x, source) %>%
-    constant_LCU_base_x_2_current_LCU(base_x, source) %>%
+    constant_USMER_base_x_2_current_LCU(base_x, source) %>e%
     current_LCU_2_current_USMER(source)
 }
 
-# Convert constant US$MER series from one base year to another
-constant_USMER_base_x_2_constant_USMER_base_y <- function(gdp, base_x, base_y, source) {
-  gdp %>%
-    constant_USMER_2_constant_LCU(base = base_x, source) %>%
-    constant_LCU_base_x_2_constant_LCU_base_y(base_x, base_y, source) %>%
-    constant_LCU_2_constant_USMER(base = base_y, source)
-}
-
 # Convert from constant US$MER in one base year to constant LCU of another
 constant_USMER_base_x_2_constant_LCU_base_y <- function(gdp, base_x, base_y, source) {
   gdp %>%
-    constant_USMER_2_constant_LCU(base = base_x, source) %>%
+    constant_USMER_2_constant_LCU(base = base_x, source) %>e%
     constant_LCU_base_x_2_constant_LCU_base_y(base_x, base_y, source)
 }
 
+# Convert constant US$MER series from one base year to another
+constant_USMER_base_x_2_constant_USMER_base_y <- function(gdp, base_x, base_y, source) {
+  gdp %>%
+    constant_USMER_base_x_2_constant_LCU_base_y(base_x, base_y, source) %>e%
+    constant_LCU_2_constant_USMER(base = base_y, source)
+}
+
 # Convert from constant US$MER in one base year to constant Int$PPP of another
 constant_USMER_base_x_2_constant_IntPPP_base_y <- function(gdp, base_x, base_y, source) {
   gdp %>%
-    constant_USMER_2_constant_LCU(base = base_x, source) %>%
-    constant_LCU_base_x_2_constant_LCU_base_y(base_x, base_y, source) %>%
+    constant_USMER_base_x_2_constant_LCU_base_y(base_x, base_y, source) %>e%
     constant_LCU_2_constant_IntPPP(base = base_y, source)
 }
 
+# Convert from constant US$MER in one base year to constant € of another
+constant_USMER_base_x_2_constant_EURO_base_y <- function(gdp, base_x, base_y, source) {
+  gdp %>%
+    constant_USMER_base_x_2_constant_USMER_base_y(base_x, base_y, source) %>e%
+    constant_USMER_2_constant_EURO(base = base_y, source)
+}
+
+#------------------------------------------------------------
+#------------------------------------------------------------
+#------------------------------------------------------------
+# Unit_in = constant €
 
+# Convert from constant € base year x to current LCU
+constant_EURO_base_x_2_current_LCU <- function(gdp, base_x, source) {
+  gdp %>%
+    constant_EURO_2_constant_USMER(base = base_x, source) %>e%
+    constant_USMER_base_x_2_current_LCU(base_x, source)
+}
+
+# Convert from constant € base year x to current Int$PPP
+constant_EURO_base_x_2_current_IntPPP <- function(gdp, base_x, source) {
+  gdp %>%
+    constant_EURO_2_constant_USMER(base = base_x, source) %>e%
+    constant_USMER_base_x_2_current_IntPPP(base_x, source)
+}
+
+# Convert from constant € base year x to current US$MER
+constant_EURO_base_x_2_current_USMER <- function(gdp, base_x, source) {
+  gdp %>%
+    constant_EURO_2_constant_USMER(base = base_x, source) %>e%
+    constant_USMER_base_x_2_current_USMER(base_x, source)
+}
+
+# Convert constant € series from one base year to another
+constant_EURO_base_x_2_constant_USMER_base_y <- function(gdp, base_x, base_y, source) {
+  gdp %>%
+    constant_EURO_2_constant_USMER(base = base_x, source) %>e%
+    constant_USMER_base_x_2_constant_USMER_base_y(base_x, base_y, source)
+}
+
+# Convert from constant € in one base year to constant LCU of another
+constant_EURO_base_x_2_constant_LCU_base_y <- function(gdp, base_x, base_y, source) {
+  gdp %>%
+    constant_EURO_2_constant_USMER(base = base_x, source) %>e%
+    constant_USMER_base_x_2_constant_LCU_base_y(base_x, base_y, source)
+}
+
+# Convert from constant € in one base year to constant Int$PPP of another
+constant_EURO_base_x_2_constant_IntPPP_base_y <- function(gdp, base_x, base_y, source) {
+  gdp %>%
+    constant_EURO_2_constant_USMER(base = base_x, source) %>e%
+    constant_USMER_base_x_2_constant_IntPPP_base_y(base_x, base_y, source)
+}
+
+# Convert from constant € in one base year to constant € of another
+constant_EURO_base_x_2_constant_EURO_base_y <- function(gdp, base_x, base_y, source) {
+  gdp %>%
+    constant_EURO_2_constant_USMER(base = base_x, source) %>e%
+    constant_USMER_base_x_2_constant_EURO_base_y(base_x, base_y, source)
+}
diff --git a/R/convertGDP.R b/R/convertGDP.R
index 9edc1bc..7d752b7 100644
--- a/R/convertGDP.R
+++ b/R/convertGDP.R
@@ -39,6 +39,7 @@
 #'     \item "constant YYYY LCU"
 #'     \item "constant YYYY Int$PPP"
 #'     \item "constant YYYY US$MER"
+#'     \item "constant YYYY €"
 #'   }
 #'   where YYYY should be replaced with a year e.g. "2010" or "2017".
 #' @param unit_out A string with the outgoing GDP unit, one of:
@@ -49,12 +50,16 @@
 #'     \item "constant YYYY LCU"
 #'     \item "constant YYYY Int$PPP"
 #'     \item "constant YYYY US$MER"
+#'     \item "constant YYYY €"
 #'   }
 #'   where YYYY should be replaced with a year e.g. "2010" or "2017".
 #' @param source A string referring to a package internal data frame containing the conversion factors, or
 #'   a data-frame that exists in the calling environment.
 #'   Use [print_source_info()](https://pik-piam.github.io/GDPuc/reference/print_source_info.html)
 #'   to learn about the available sources.
+#' @param use_USA_deflator_for_all TRUE or FALSE (default). If TRUE, then only the USA deflator is used to adjust for
+#'   inflation, regardless of the country codes provided. This is a very specific deviation from the correct conversion
+#'   process, which nevertheless is often used in the integrated assessment community. Use carefully!
 #' @param with_regions NULL or a data-frame. The data-frame should be "country to region
 #'   mapping": one column named "iso3c" with iso3c country codes, and one column named
 #'   "region" with region codes to which the countries belong. Any regions in the gdp
@@ -71,6 +76,8 @@
 #'     \item "regional_average": missing conversion factors in the source object are replaced with
 #'     the regional average of the region to which the country belongs. This requires a region-mapping to
 #'     be passed to the function, see the with_regions argument.
+#'     \item "with USA": missing conversion factors in the source object are replaced with
+#'     the conversion factors of the USA.
 #'   }
 #'   Can also be a vector with "linear" as first element, e.g. c("linear", 0) or c("linear", "no_conversion"),
 #'   in which case, the operations are done in sequence.
@@ -82,14 +89,22 @@
 #' @return The gdp argument, with the values in the "value" column, converted to unit_out. If the argument
 #'   return_cfs is TRUE, then a list is returned with the converted GDP under "result", and the conversion
 #'   factors used under "cfs".
-#' @seealso The [countrycode](https://github.com/vincentarelbundock/countrycode)
-#'   package to convert country codes.
-#' @importFrom magrittr %>%
+#' @seealso The [countrycode](https://github.com/vincentarelbundock/countrycode) package to convert country codes.
+#' @examples
+#'   my_tbble <- tibble::tibble(iso3c = "FRA",
+#'                              year = 2013,
+#'                              value = 100)
+#'
+#'   convertGDP(gdp = my_tbble,
+#'              unit_in = "current LCU",
+#'              unit_out = "constant 2015 Int$PPP")
+#'
 #' @export
 convertGDP <- function(gdp,
                        unit_in,
                        unit_out,
                        source = "wb_wdi",
+                       use_USA_deflator_for_all = FALSE,
                        with_regions = NULL,
                        replace_NAs = NULL,
                        verbose = getOption("GDPuc.verbose", default = FALSE),
@@ -110,7 +125,7 @@ convertGDP <- function(gdp,
   }
 
   # Transform user input for internal use, while performing some last consistency checks
-  internal <- transform_user_input(gdp, unit_in, unit_out, source, with_regions, replace_NAs)
+  internal <- transform_user_input(gdp, unit_in, unit_out, source, use_USA_deflator_for_all, with_regions, replace_NAs)
 
   # Avoid NOTE in package check for CRAN
   . <- NULL
@@ -118,7 +133,9 @@ convertGDP <- function(gdp,
   f <- paste0(internal$unit_in, "_2_", internal$unit_out) %>%
     gsub(" ", "_", .) %>%
     gsub("_YYYY", "", .) %>%
-    gsub("\\$", "", .)
+    gsub("\\$", "", .) %>%
+    # \u20ac is the ascii code for the € sign
+    gsub("\u20ac", "EURO", .)
 
   # Get list of function arguments
   a <- list("gdp" = internal$gdp, "source" = internal$source) %>%
@@ -154,3 +171,47 @@ convertGDP <- function(gdp,
     return(x)
   }
 }
+
+#' @describeIn convertGDP Short cut for `convertGDP(..., source = "wb_wdi_cpi")`
+#' @param ... Arguments passed on to `convertGDP()`
+#' @examples
+#'   # Convert using the CPI as deflator.
+#'   convertGDP(gdp = my_tbble,
+#'              unit_in = "current LCU",
+#'              unit_out = "constant 2015 Int$PPP",
+#'              source = "wb_wdi_cpi")
+#'   # Or using the shortcut `convertCPI()`
+#'   convertCPI(gdp = my_tbble,
+#'              unit_in = "current LCU",
+#'              unit_out = "constant 2015 Int$PPP")
+#'
+#' @export
+convertCPI <- function(...) convertGDP(..., source = "wb_wdi_cpi")
+
+#' @describeIn convertGDP Convert a single value, while specifying iso3c code and year. Simpler than creating a
+#'   single row tibble.
+#' @param x Number to convert
+#' @param iso3c Country code
+#' @param year Year of value. Is given the default value of 2000, since it only plays a role when converting from
+#'   or to current currencies. This facilitates the conversion between constant currencies.
+#' @examples
+#'   # Convert a single value quickly
+#'   convertSingle(x = 100,
+#'                 iso3c = "FRA",
+#'                 year = 2013,
+#'                 unit_in = "current LCU",
+#'                 unit_out = "constant 2015 Int$PPP")
+#' @export
+convertSingle <- function(x,
+                          iso3c,
+                          year = 2000,
+                          ...) {
+  tib <- tibble::tibble("iso3c" = iso3c, "year" = year, "value" = x)
+  tib_c <- convertGDP(gdp = tib, ...)
+
+  if (tibble::is_tibble(tib_c)) {
+    return(tib_c$value)
+  } else {
+    return(tib_c)
+  }
+}
diff --git a/R/elemental_conversions.R b/R/elemental_conversions.R
index 5c1c624..7cdf3ae 100644
--- a/R/elemental_conversions.R
+++ b/R/elemental_conversions.R
@@ -273,3 +273,54 @@ constant_USMER_2_constant_LCU <- function(gdp, base, source) {
     dplyr::mutate(value = .data$value * .data$`MER (LCU per US$)`,
                   .keep = "unused")
 }
+
+# Convert from constant US$MER to constant EURO
+constant_USMER_2_constant_EURO <- function(gdp, base, source) {
+  MER_EURO_per_DOLLAR <- source %>%
+    dplyr::filter(.data$year == base, .data$iso3c == "DEU") %>%
+    dplyr::pull(.data$`MER (LCU per US$)`)
+
+  MER_base <- source %>%
+    dplyr::filter(.data$year == base) %>%
+    dplyr::mutate("MER (LCU per US$)" = MER_EURO_per_DOLLAR) %>%
+    dplyr::select("iso3c", "MER (LCU per US$)")
+
+  cli_elemental(from = glue::glue("constant {base} US$MER"),
+                to = glue::glue("constant {base} \u20ac"),
+                with = glue::glue("{base} MER"),
+                unit = "(\u20ac per US$)",
+                val = dplyr::filter(MER_base, .data$iso3c %in% unique(gdp$iso3c)))
+
+  gdp %>%
+    dplyr::left_join(MER_base, by = "iso3c") %>%
+    dplyr::mutate(value = .data$value * .data$`MER (LCU per US$)`,
+                  .keep = "unused")
+}
+
+
+#------------------------------------------------------------
+#------------------------------------------------------------
+#------------------------------------------------------------
+# Unit_in = constant €
+
+constant_EURO_2_constant_USMER <- function(gdp, base, source) {
+  MER_EURO_per_DOLLAR <- source %>%
+    dplyr::filter(.data$year == base, .data$iso3c == "DEU") %>%
+    dplyr::pull(.data$`MER (LCU per US$)`)
+
+  MER_base <- source %>%
+    dplyr::filter(.data$year == base) %>%
+    dplyr::mutate("MER (LCU per US$)" = MER_EURO_per_DOLLAR) %>%
+    dplyr::select("iso3c", "MER (LCU per US$)")
+
+  cli_elemental(from = glue::glue("constant {base} \u20ac"),
+                to = glue::glue("constant {base} US$MER"),
+                with = glue::glue("{base} MER"),
+                unit = "(\u20ac per US$)",
+                val = dplyr::filter(MER_base, .data$iso3c %in% unique(gdp$iso3c)))
+
+  gdp %>%
+    dplyr::left_join(MER_base, by = "iso3c") %>%
+    dplyr::mutate(value = .data$value / .data$`MER (LCU per US$)`,
+                  .keep = "unused")
+}
diff --git a/R/print_source_info.R b/R/print_source_info.R
index 208b926..f7cdc30 100644
--- a/R/print_source_info.R
+++ b/R/print_source_info.R
@@ -7,27 +7,38 @@
 #'  html-link and an associated note. Calling the function without any argument will print information on all
 #'  available sources.
 #'
-#' @param source The name of one of the internal sources:
+#' @param source Empty, or the name of one of the internal sources:
 #'   \enumerate{
 #'     \item "wb_wdi"
 #'     \item "wb_wdi_linked"
+#'     \item "wb_wdi_cpi"
 #'   }
 #' @return No return value, called for side effects.
+#' @examples
+#' print_source_info()
+#'
 #' @export
 print_source_info <- function(source) {
   if (missing(source)) cli::cli_alert_info("Sources available:")
   if (missing(source) || source == "wb_wdi") {
     cli_source_info(name = "wb_wdi",
                     origin = "The World Bank's World Development Indicator Database",
-                    date = "Downloaded on the 22 of Oktober 2021",
+                    date = "Downloaded on the 2nd of January 2024",
                     html = "https://databank.worldbank.org/source/world-development-indicators",
-                    note = "Uses the standard deflator.")
+                    note = "Uses the GDP deflator.")
   }
   if (missing(source) || source == "wb_wdi_linked") {
     cli_source_info(name = "wb_wdi_linked",
                     origin = "The World Bank's World Development Indicator Database",
-                    date = "Downloaded on the 22 of Oktober 2021",
+                    date = "Downloaded on the 2nd of January 2024",
+                    html = "https://databank.worldbank.org/source/world-development-indicators",
+                    note = "Uses the linked GDP deflator.")
+  }
+  if (missing(source) || source == "wb_wdi_cpi") {
+    cli_source_info(name = "wb_wdi_cpi",
+                    origin = "The World Bank's World Development Indicator Database",
+                    date = "Downloaded on the 2nd of January 2024",
                     html = "https://databank.worldbank.org/source/world-development-indicators",
-                    note = "Uses the linked deflator.")
+                    note = "Uses the CPI as deflator.")
   }
 }
diff --git a/R/sysdata.rda b/R/sysdata.rda
index 759d574..6da5cd5 100644
Binary files a/R/sysdata.rda and b/R/sysdata.rda differ
diff --git a/R/transform_user_input.R b/R/transform_user_input.R
index e80cf7c..113fd26 100644
--- a/R/transform_user_input.R
+++ b/R/transform_user_input.R
@@ -1,10 +1,10 @@
 # Transform user input for package internal use
-transform_user_input <- function(gdp, unit_in, unit_out, source, with_regions, replace_NAs) {
+transform_user_input <- function(gdp, unit_in, unit_out, source, use_USA_deflator_for_all, with_regions, replace_NAs) {
   . <- NULL
 
   # Convert to tibble, if necessary
   if (class(gdp)[1] == "magpie") {
-    gdp <- mag_2_tibb(gdp)
+    gdp <- tibble::as_tibble(gdp) %>% dplyr::rename(tidyselect::any_of(c("iso3c" = "region")))
   }
 
   # Extract base years if they exist, and adjust string
@@ -68,9 +68,13 @@ transform_user_input <- function(gdp, unit_in, unit_out, source, with_regions, r
     abort("Incompatible 'gdp' and 'source'. No information in source {crayon::bold(source_name)} for years in 'gdp'.")
   }
 
-  # Use different source if required
-  if (!is.null(replace_NAs) && !any(sapply(c(NA, 0, "no_conversion"), setequal, replace_NAs))) {
-    source <- adapt_source(gdp, source, with_regions, replace_NAs)
+  # Use different source if required by the replace_NAs argument
+  if (use_USA_deflator_for_all ||
+      (!is.null(replace_NAs) && !any(sapply(c(NA, 0, "no_conversion"), setequal, replace_NAs))) ) {
+    if (use_USA_deflator_for_all || replace_NAs[1] == "with_USA") source <- adapt_source_USA(gdp, source, replace_NAs)
+    if (!is.null(replace_NAs) && !any(sapply(c(NA, 0, "no_conversion", "with_USA"), setequal, replace_NAs))){
+      source <- adapt_source(gdp, source, with_regions, replace_NAs)
+    }
     source_name <- paste0(source_name, "_adapted")
   }
 
diff --git a/R/ui.R b/R/ui.R
index 16125bf..01c52b3 100644
--- a/R/ui.R
+++ b/R/ui.R
@@ -22,7 +22,7 @@ cli_elemental <- function(from, to, with, unit, val) {
     cli::cli({
       cli::cli_text("{.strong {from}} {crayon::green(cli::symbol$arrow_right)} {.strong {to}}")
       cli::cli_text("{crayon::blue(with)}{cli::qty(as.character(values))}{?s} in {unit} used:")
-      cli::cli_dl(c(values))
+      cli::cli_dl(c(signif(values, 6)))
     })
   }
   cli_inform(my_cli)
diff --git a/R/utils.R b/R/utils.R
index d6370ca..750a254 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -1,3 +1,6 @@
+# Eager pipe. Used to make sure the messages of the elemental conversion are printed in the right order.
+`%>e%` <- magrittr::pipe_eager_lexical
+
 smart_select_iso3c <- function(gdp) {
   gdp %>%
     dplyr::select(tidyselect::vars_select_helpers$where(
@@ -17,12 +20,3 @@ smart_select_year <- function(gdp) {
     )) %>%
     colnames()
 }
-
-mag_2_tibb <- function(gdp) {
-  gdp %>%
-    magclass::as.data.frame() %>%
-    tibble::as_tibble() %>%
-    dplyr::select(-"Cell") %>%
-    dplyr::rename("iso3c" = "Region", "year" = "Year", "value" = "Value") %>%
-    dplyr::mutate(year = as.integer(as.character(.data$year)))
-}
diff --git a/README.Rmd b/README.Rmd
index a223674..f5b9b0c 100644
--- a/README.Rmd
+++ b/README.Rmd
@@ -24,7 +24,7 @@ knitr::opts_chunk$set(
 
 GDPuc (a.k.a. the GDP unit-converter) provides a simple function to convert GDP time-series data from one unit to another.
 
-**To note:** The default conversion parameters are from the World Bank's World Development Indicators (WDI) database (see [link](https://databank.worldbank.org/source/world-development-indicators)). The current parameters are from **October 2021**, with the next update planned for October 2022.
+**To note:** The default conversion parameters are from the World Bank's World Development Indicators (WDI) database (see [link](https://databank.worldbank.org/source/world-development-indicators)). The current parameters are from **January 2nd 2024**, with the next update planned for January 2025.
 
 ## Installation
 
diff --git a/README.md b/README.md
index 9ed56a1..4b316ee 100644
--- a/README.md
+++ b/README.md
@@ -20,8 +20,8 @@ convert GDP time-series data from one unit to another.
 **To note:** The default conversion parameters are from the World Bank’s
 World Development Indicators (WDI) database (see
 [link](https://databank.worldbank.org/source/world-development-indicators)).
-The current parameters are from **October 2021**, with the next update
-planned for October 2022.
+The current parameters are from **January 2nd 2024**, with the next
+update planned for January 2025.
 
 ## Installation
 
diff --git a/data-raw/create_internal_sources.R b/data-raw/create_internal_sources.R
index 7a067df..0db9b47 100644
--- a/data-raw/create_internal_sources.R
+++ b/data-raw/create_internal_sources.R
@@ -15,7 +15,8 @@ my_vars <- c(
   "Population, total",
   "GDP deflator (base year varies by country)",
   "GDP deflator: linked series (base year varies by country)",
-  "DEC alternative conversion factor (LCU per US$)"
+  "DEC alternative conversion factor (LCU per US$)",
+  "Consumer price index (2010 = 100)"
 )
 
 my_info <- WDI::WDIsearch(
@@ -32,21 +33,24 @@ my_info <- WDI::WDIsearch(
   tibble::as_tibble()
 
 # Download data, remove aggregates and do some pivoting and renaming
-my_data <- WDI::WDI(indicator = my_info$indicator, extra = TRUE) %>%
-  tibble::as_tibble() %>%
-  dplyr::filter(!is.na(region) & region != "Aggregates") %>%
-  dplyr::arrange(iso3c, year) %>%
-  dplyr::select(iso3c, year, tidyselect::contains(my_info$indicator)) %>%
-  tidyr::pivot_longer(cols = tidyselect::contains(my_info$indicator), names_to = "id") %>%
-  dplyr::mutate(name = stringr::str_replace_all(id, my_info$name %>%
-                                                  rlang::set_names(paste0("^", my_info$indicator, "$")))) %>%
-  dplyr::select(iso3c, year, id, name, value)
+my_data <- purrr::map2(my_info$indicator,
+                       my_info$name,
+                       ~ WDI::WDI(indicator = .x, extra = TRUE) %>%
+                         tibble::as_tibble() %>%
+                         dplyr::filter(!is.na(region) & region != "Aggregates") %>%
+                         dplyr::arrange(iso3c, year) %>%
+                         dplyr::select(iso3c, year, tidyselect::contains(.x)) %>%
+                         tidyr::pivot_longer(cols = tidyselect::contains(.x), names_to = "id") %>%
+                         dplyr::mutate(name = .y) %>%
+                         dplyr::select(iso3c, year, id, name, value)) %>%
+  purrr::list_rbind()
 
 wb_wdi <- my_data %>%
   dplyr::select(-id) %>%
   tidyr::pivot_wider(names_from = name) %>%
   dplyr::mutate(`GDP deflator: linked series` = `GDP deflator: linked series (base year varies by country)` / 100,
                 `GDP deflator` = `GDP deflator (base year varies by country)` / 100,
+                `CPI` = `Consumer price index (2010 = 100)` / 100,
                 `MER (LCU per US$)` = `DEC alternative conversion factor (LCU per US$)`)
 
 wb_wdi_linked <- wb_wdi %>%
@@ -56,9 +60,16 @@ wb_wdi_linked <- wb_wdi %>%
                 `PPP conversion factor, GDP (LCU per international $)`,
                 `MER (LCU per US$)`)
 
+wb_wdi_cpi <- wb_wdi %>%
+  dplyr::select(iso3c,
+                year,
+                `GDP deflator` = `CPI`,
+                `PPP conversion factor, GDP (LCU per international $)`,
+                `MER (LCU per US$)`)
+
 # For now, IMF is removed due to copyright issues
 #usethis::use_data(imf_weo, wb_wdi, wb_wdi_linked, internal = TRUE, overwrite = TRUE)
-usethis::use_data(wb_wdi, wb_wdi_linked, internal = TRUE, overwrite = TRUE)
+usethis::use_data(wb_wdi, wb_wdi_linked, wb_wdi_cpi, internal = TRUE, overwrite = TRUE)
 
 
 
diff --git a/man/GDPuc-package.Rd b/man/GDPuc-package.Rd
index 5c2df6e..3e410b5 100644
--- a/man/GDPuc-package.Rd
+++ b/man/GDPuc-package.Rd
@@ -10,5 +10,18 @@
 
 Convert GDP time series data from one unit to another. All common GDP units are included, i.e. current and constant
 local currency units, US$ via market exchange rates and international dollars via purchasing power parities.
+}
+\seealso{
+Useful links:
+\itemize{
+  \item \url{https://github.com/pik-piam/GDPuc}
+  \item \url{https://pik-piam.github.io/GDPuc/}
+  \item Report bugs at \url{https://github.com/pik-piam/GDPuc/issues}
+}
+
+}
+\author{
+\strong{Maintainer}: Johannes Koch \email{jokoch@pik-potsdam.de}
+
 }
 \keyword{internal}
diff --git a/man/convertGDP.Rd b/man/convertGDP.Rd
index a78d051..6d77e87 100644
--- a/man/convertGDP.Rd
+++ b/man/convertGDP.Rd
@@ -2,6 +2,8 @@
 % Please edit documentation in R/convertGDP.R
 \name{convertGDP}
 \alias{convertGDP}
+\alias{convertCPI}
+\alias{convertSingle}
 \title{Convert GDP data}
 \usage{
 convertGDP(
@@ -9,11 +11,16 @@ convertGDP(
   unit_in,
   unit_out,
   source = "wb_wdi",
+  use_USA_deflator_for_all = FALSE,
   with_regions = NULL,
   replace_NAs = NULL,
   verbose = getOption("GDPuc.verbose", default = FALSE),
   return_cfs = FALSE
 )
+
+convertCPI(...)
+
+convertSingle(x, iso3c, year = 2000, ...)
 }
 \arguments{
 \item{gdp}{A tibble, data frame or magpie object, the latter of which
@@ -34,6 +41,7 @@ package to be installed. The data-frame needs to have at least 3 columns:
 \item "constant YYYY LCU"
 \item "constant YYYY Int$PPP"
 \item "constant YYYY US$MER"
+\item "constant YYYY €"
 }
 where YYYY should be replaced with a year e.g. "2010" or "2017".}
 
@@ -45,6 +53,7 @@ where YYYY should be replaced with a year e.g. "2010" or "2017".}
 \item "constant YYYY LCU"
 \item "constant YYYY Int$PPP"
 \item "constant YYYY US$MER"
+\item "constant YYYY €"
 }
 where YYYY should be replaced with a year e.g. "2010" or "2017".}
 
@@ -53,6 +62,10 @@ a data-frame that exists in the calling environment.
 Use \href{https://pik-piam.github.io/GDPuc/reference/print_source_info.html}{print_source_info()}
 to learn about the available sources.}
 
+\item{use_USA_deflator_for_all}{TRUE or FALSE (default). If TRUE, then only the USA deflator is used to adjust for
+inflation, regardless of the country codes provided. This is a very specific deviation from the correct conversion
+process, which nevertheless is often used in the integrated assessment community. Use carefully!}
+
 \item{with_regions}{NULL or a data-frame. The data-frame should be "country to region
 mapping": one column named "iso3c" with iso3c country codes, and one column named
 "region" with region codes to which the countries belong. Any regions in the gdp
@@ -70,6 +83,8 @@ For the extrapolation, the closest 5 data points are used.
 \item "regional_average": missing conversion factors in the source object are replaced with
 the regional average of the region to which the country belongs. This requires a region-mapping to
 be passed to the function, see the with_regions argument.
+\item "with USA": missing conversion factors in the source object are replaced with
+the conversion factors of the USA.
 }
 Can also be a vector with "linear" as first element, e.g. c("linear", 0) or c("linear", "no_conversion"),
 in which case, the operations are done in sequence.}
@@ -80,6 +95,15 @@ GDPuc.verbose option, which is FALSE if not set to TRUE by the user.}
 \item{return_cfs}{TRUE or FALSE. Set to TRUE to additionally return a tibble with the conversion factors
 used. In that case a list is returned with the converted GDP under "result", and the conversion factors
 used under "cfs".}
+
+\item{...}{Arguments passed on to \code{convertGDP()}}
+
+\item{x}{Number to convert}
+
+\item{iso3c}{Country code}
+
+\item{year}{Year of value. Is given the default value of 2000, since it only plays a role when converting from
+or to current currencies. This facilitates the conversion between constant currencies.}
 }
 \value{
 The gdp argument, with the values in the "value" column, converted to unit_out. If the argument
@@ -108,7 +132,40 @@ The base year of the deflator can be any year, and can be country-specific.
 wit PPP exchange rate values.
 }
 }
+\section{Functions}{
+\itemize{
+\item \code{convertCPI()}: Short cut for \code{convertGDP(..., source = "wb_wdi_cpi")}
+
+\item \code{convertSingle()}: Convert a single value, while specifying iso3c code and year. Simpler than creating a
+single row tibble.
+
+}}
+\examples{
+  my_tbble <- tibble::tibble(iso3c = "FRA",
+                             year = 2013,
+                             value = 100)
+
+  convertGDP(gdp = my_tbble,
+             unit_in = "current LCU",
+             unit_out = "constant 2015 Int$PPP")
+
+  # Convert using the CPI as deflator.
+  convertGDP(gdp = my_tbble,
+             unit_in = "current LCU",
+             unit_out = "constant 2015 Int$PPP",
+             source = "wb_wdi_cpi")
+  # Or using the shortcut `convertCPI()`
+  convertCPI(gdp = my_tbble,
+             unit_in = "current LCU",
+             unit_out = "constant 2015 Int$PPP")
+
+  # Convert a single value quickly
+  convertSingle(x = 100,
+                iso3c = "FRA",
+                year = 2013,
+                unit_in = "current LCU",
+                unit_out = "constant 2015 Int$PPP")
+}
 \seealso{
-The \href{https://github.com/vincentarelbundock/countrycode}{countrycode}
-package to convert country codes.
+The \href{https://github.com/vincentarelbundock/countrycode}{countrycode} package to convert country codes.
 }
diff --git a/man/print_source_info.Rd b/man/print_source_info.Rd
index 8564196..b7eb945 100644
--- a/man/print_source_info.Rd
+++ b/man/print_source_info.Rd
@@ -7,10 +7,11 @@
 print_source_info(source)
 }
 \arguments{
-\item{source}{The name of one of the internal sources:
+\item{source}{Empty, or the name of one of the internal sources:
 \enumerate{
 \item "wb_wdi"
 \item "wb_wdi_linked"
+\item "wb_wdi_cpi"
 }}
 }
 \value{
@@ -23,3 +24,7 @@ Print detailed information on conversion factor sources to the screen. Informati
 html-link and an associated note. Calling the function without any argument will print information on all
 available sources.
 }
+\examples{
+print_source_info()
+
+}
diff --git a/tests/testthat/setup-global_vars.R b/tests/testthat/setup-global_vars.R
index 41ed278..d360f3a 100644
--- a/tests/testthat/setup-global_vars.R
+++ b/tests/testthat/setup-global_vars.R
@@ -1,10 +1,12 @@
 # Base year of constant US$MER GDP series in wdi data
-year_USMER <- 2010
+year_USMER <- 2015
 regex_var_USMER <- paste("GDP \\(constant", year_USMER, "US\\$\\)")
+var_USMER <- paste("GDP (constant", year_USMER, "US$)")
 
 # Base year of constant Int$PPP GDP series in wb_wdi
 year_IntPPP <- 2017
 regex_var_IntPPP <- paste("GDP, PPP \\(constant", year_IntPPP, "international \\$\\)")
+var_IntPPP <- paste("GDP, PPP (constant", year_IntPPP, "international $)")
 
-# WSM = Samoa has inconsistent WDI data...
-bad_countries <- c("WSM")
+# PAN = Panama has inconsistent WDI data...
+bad_countries <- c("PAN")
diff --git a/tests/testthat/test-check_user_input.R b/tests/testthat/test-01_check_user_input.R
similarity index 57%
rename from tests/testthat/test-check_user_input.R
rename to tests/testthat/test-01_check_user_input.R
index 2d4bfe7..fb53ba6 100644
--- a/tests/testthat/test-check_user_input.R
+++ b/tests/testthat/test-01_check_user_input.R
@@ -51,11 +51,29 @@ test_that("with_regions argument", {
   unit_out <- "current US$MER"
   s <- wb_wdi
 
-  expect_error(check_user_input(gdp, unit_in, unit_out, source = s, with_regions = "blabla"))
+  expect_error(check_user_input(gdp,
+                                unit_in,
+                                unit_out,
+                                source = s,
+                                use_USA_deflator_for_all = FALSE,
+                                with_regions = "blabla"))
+
   with_regions <- tibble::tibble("blabla" = "FRA", "region" = "USA")
-  expect_error(check_user_input(gdp, unit_in, unit_out,  source = s, with_regions = with_regions))
+  expect_error(check_user_input(gdp,
+                                unit_in,
+                                unit_out,
+                                source = s,
+                                use_USA_deflator_for_all = FALSE,
+                                with_regions = with_regions))
+
   with_regions <- tibble::tibble("iso3c" = "FRA", "region" = "USA")
-  expect_error(check_user_input(gdp, unit_in, "current LCU",  source = s, with_regions = with_regions))
+  expect_error(check_user_input(gdp,
+                                unit_in,
+                                "current LCU",
+                                source = s,
+                                use_USA_deflator_for_all = FALSE,
+                                with_regions = with_regions))
+
   my_bad_source <- wb_wdi %>% dplyr::select(
     "iso3c",
     "year",
@@ -64,7 +82,12 @@ test_that("with_regions argument", {
     "PPP conversion factor, GDP (LCU per international $)"
   )
   s <- my_bad_source
-  expect_error(check_user_input(gdp, unit_in, unit_out,  source = s, with_regions = with_regions))
+  expect_error(check_user_input(gdp,
+                                unit_in,
+                                unit_out,
+                                source = s,
+                                use_USA_deflator_for_all = FALSE,
+                                with_regions = with_regions))
 })
 
 test_that("replace_NAs argument", {
@@ -74,18 +97,42 @@ test_that("replace_NAs argument", {
   unit_out <- "current US$MER"
   s <- wb_wdi
 
-  expect_error(check_user_input(gdp, unit_in, unit_out,  source = s, replace_NAs = 2, with_regions = NULL),
+  expect_error(check_user_input(gdp,
+                                unit_in,
+                                unit_out,
+                                source = s,
+                                use_USA_deflator_for_all = FALSE,
+                                replace_NAs = 2,
+                                with_regions = NULL),
                glue::glue("Invalid 'replace_NAs' argument. Has to be either NULL, NA, 0, 1, no_conversion, linear, \\
-                          regional_average or a combination of the above."))
-  expect_error(check_user_input(gdp, unit_in, unit_out,  source = s, replace_NAs = c(0, 1), with_regions = NULL),
+                          regional_average, with_USA or a combination of the above."))
+  expect_error(check_user_input(gdp,
+                                unit_in,
+                                unit_out,
+                                source = s,
+                                use_USA_deflator_for_all = FALSE,
+                                replace_NAs = c(0, 1),
+                                with_regions = NULL),
                glue::glue("Invalid 'replace_NAs' argument. The only accepted combinations of arguments start with \\
                           'linear', e.g. c\\('linear', 'no_conversion'\\)."))
   expect_error(
-    check_user_input(gdp, unit_in, unit_out,  source = s, replace_NAs = "linear_regional_average", with_regions = NULL)
+    check_user_input(gdp,
+                     unit_in,
+                     unit_out,
+                     source = s,
+                     use_USA_deflator_for_all = FALSE,
+                     replace_NAs = "linear_regional_average",
+                     with_regions = NULL)
   )
 
   expect_error(
-    check_user_input(gdp, unit_in, unit_out,  source = s, replace_NAs = "regional_average", with_regions = NULL),
+    check_user_input(gdp,
+                     unit_in,
+                     unit_out,
+                     source = s,
+                     use_USA_deflator_for_all = FALSE,
+                     replace_NAs = "regional_average",
+                     with_regions = NULL),
     glue::glue("Using 'regional_average' requires a region mapping. The 'with_regions' argument can't be NULL.")
   )
 })
@@ -97,14 +144,21 @@ test_that("boolean arguments", {
   unit_out <- "current US$MER"
   s <- wb_wdi
 
-  expect_error(check_user_input(gdp, unit_in, unit_out,  source = s,
-                                with_regions = NULL, replace_NAs = NULL, verbose = "blabla"))
+  expect_error(check_user_input(gdp,
+                                unit_in,
+                                unit_out,
+                                source = s,
+                                use_USA_deflator_for_all = FALSE,
+                                with_regions = NULL,
+                                replace_NAs = NULL,
+                                verbose = "blabla"))
 
   expect_error(check_user_input(
     gdp,
     unit_in,
     unit_out,
     source = s,
+    use_USA_deflator_for_all = FALSE,
     with_regions = NULL,
     replace_NAs = NULL,
     verbose = TRUE,
diff --git a/tests/testthat/test-transform_user_input.R b/tests/testthat/test-02_transform_user_input.R
similarity index 100%
rename from tests/testthat/test-transform_user_input.R
rename to tests/testthat/test-02_transform_user_input.R
diff --git a/tests/testthat/test-elemental_conversions.R b/tests/testthat/test-03_elemental_conversions.R
similarity index 69%
rename from tests/testthat/test-elemental_conversions.R
rename to tests/testthat/test-03_elemental_conversions.R
index 7183a48..3c8bc2b 100644
--- a/tests/testthat/test-elemental_conversions.R
+++ b/tests/testthat/test-03_elemental_conversions.R
@@ -3,7 +3,7 @@
 #------------------------------------------------------------
 # Unit_in = current_LCU
 
-test_that("current_LCU_2_constant_LCU_base_x wb_wdi", {
+test_that("current_LCU_2_constant_LCU_base_y", {
   country_base_years <- wb_wdi %>%
     dplyr::filter(`GDP deflator (base year varies by country)` == 100) %>%
     dplyr::select("iso3c", "year")
@@ -39,41 +39,41 @@ test_that("current_LCU_2_constant_LCU_base_x wb_wdi", {
   }
 })
 
-# test_that("current_LCU_2_constant_LCU_base_y linked series", {
-#   country_base_years <- wb_wdi_linked %>%
-#     dplyr::filter(`GDP deflator` == 1) %>%
-#     dplyr::select("iso3c", "year")
-#
-#   my_years <- country_base_years %>%
-#     dplyr::group_by(year) %>%
-#     dplyr::count() %>%
-#     dplyr::arrange(-n) %>%
-#     dplyr::pull(year)
-#
-#   for (my_base_year in my_years) {
-#     my_countries <- country_base_years %>%
-#       dplyr::filter(year == my_base_year) %>%
-#       dplyr::pull(iso3c)
-#
-#     gdp_in <- wb_wdi %>%
-#       dplyr::filter(iso3c %in% my_countries,
-#                     !is.na(`GDP (constant LCU)`)) %>%
-#       dplyr::select("iso3c", "year", "value" = `GDP: linked series (current LCU)`)
-#
-#     gdp_conv <- current_LCU_2_constant_LCU_base_y(gdp_in, my_base_year, wb_wdi_linked) %>%
-#       dplyr::filter(!is.na(value))
-#
-#     gdp_out <- wb_wdi %>%
-#       dplyr::right_join(gdp_conv, by = c("iso3c", "year")) %>%
-#       dplyr::select("iso3c", "year", "value" = `GDP (constant LCU)`)
-#
-#     for (country in unique(gdp_conv$iso3c)) {
-#       expect_equal(gdp_conv %>% dplyr::filter(iso3c == country),
-#                    gdp_out %>% dplyr::filter(iso3c == country),
-#                    label = country)
-#     }
-#   }
-# })
+test_that("current_LCU_2_constant_LCU_base_y linked series", {
+  country_base_years <- wb_wdi_linked %>%
+    dplyr::filter(`GDP deflator` == 1) %>%
+    dplyr::select("iso3c", "year")
+
+  my_years <- country_base_years %>%
+    dplyr::group_by(year) %>%
+    dplyr::count() %>%
+    dplyr::arrange(-n) %>%
+    dplyr::pull(year)
+
+  for (my_base_year in my_years) {
+    my_countries <- country_base_years %>%
+      dplyr::filter(year == my_base_year) %>%
+      dplyr::pull(iso3c)
+
+    gdp_in <- wb_wdi %>%
+      dplyr::filter(iso3c %in% my_countries,
+                    !is.na(`GDP (constant LCU)`)) %>%
+      dplyr::select("iso3c", "year", "value" = `GDP: linked series (current LCU)`)
+
+    gdp_conv <- current_LCU_2_constant_LCU_base_y(gdp_in, my_base_year, wb_wdi_linked) %>%
+      dplyr::filter(!is.na(value))
+
+    gdp_out <- wb_wdi %>%
+      dplyr::right_join(gdp_conv, by = c("iso3c", "year")) %>%
+      dplyr::select("iso3c", "year", "value" = `GDP (constant LCU)`)
+
+    for (country in unique(gdp_conv$iso3c)) {
+      expect_equal(gdp_conv %>% dplyr::filter(iso3c == country),
+                   gdp_out %>% dplyr::filter(iso3c == country),
+                   label = country)
+    }
+  }
+})
 
 test_that("current_LCU_2_current_IntPPP", {
   gdp_in <- wb_wdi %>%
@@ -179,7 +179,7 @@ test_that("constant_LCU_2_constant_IntPPP", {
 
   gdp_in <- wb_wdi %>%
     dplyr::filter(iso3c %in% my_countries,
-                  dplyr::if_all(tidyselect::matches(regex_var_IntPPP), ~!is.na(.x))) %>%
+                  !dplyr::if_any(tidyselect::matches(regex_var_IntPPP), ~ is.na(.x))) %>%
     dplyr::select("iso3c", "year", "value" = `GDP (constant LCU)`)
 
   gdp_conv <- constant_LCU_2_constant_IntPPP(gdp_in, year_IntPPP, wb_wdi) %>%
@@ -207,7 +207,7 @@ test_that("constant_LCU_2_constant_USMER", {
 
   gdp_in <- wb_wdi %>%
     dplyr::filter(iso3c %in% my_countries,
-                  dplyr::if_all(tidyselect::matches(regex_var_USMER), ~!is.na(.x))) %>%
+                  !dplyr::if_any(tidyselect::matches(regex_var_USMER), ~ is.na(.x))) %>%
     dplyr::select("iso3c", "year", "value" = `GDP (constant LCU)`)
 
   gdp_conv <- constant_LCU_2_constant_USMER(gdp_in, year_USMER, wb_wdi) %>%
@@ -292,3 +292,68 @@ test_that("constant_USMER_2_constant_LCU", {
   }
 })
 
+test_that("constant_USMER_2_constant_EURO", {
+  country_base_years <- wb_wdi %>%
+    dplyr::filter(`GDP deflator (base year varies by country)` == 100) %>%
+    dplyr::select("iso3c", "year")
+
+  euro_countries <- c("AUT", "BEL", "HRV", "CYP", "EST", "FIN", "FRA", "DEU", "GRC", "IRL",
+                      "ITA", "LVA", "LTU", "LUX", "NLD", "PRT", "SVK", "SVN", "ESP")
+
+  my_countries <- country_base_years %>%
+    dplyr::filter(year == year_USMER, iso3c %in% euro_countries) %>%
+    dplyr::pull(iso3c)
+
+  gdp_in <- wb_wdi %>%
+    dplyr::filter(iso3c %in% my_countries,
+                  !is.na(`GDP (constant LCU)`)) %>%
+    dplyr::select("iso3c", "year", "value" = tidyselect::matches(regex_var_USMER))
+
+  gdp_conv <- constant_USMER_2_constant_EURO(gdp_in, year_USMER, wb_wdi) %>%
+    dplyr::filter(!is.na(value))
+
+  gdp_out <- constant_USMER_2_constant_LCU(gdp_in, year_USMER, wb_wdi) %>%
+    dplyr::filter(!is.na(value))
+
+  for (country in unique(gdp_conv$iso3c)) {
+    expect_equal(gdp_conv %>% dplyr::filter(iso3c == country),
+                 gdp_out %>% dplyr::filter(iso3c == country),
+                 label = country)
+  }
+})
+
+
+#------------------------------------------------------------
+#------------------------------------------------------------
+#------------------------------------------------------------
+# Unit_in = constant_EURO
+
+test_that("constant_EURO_2_constant_USMER", {
+  country_base_years <- wb_wdi %>%
+    dplyr::filter(`GDP deflator (base year varies by country)` == 100) %>%
+    dplyr::select("iso3c", "year")
+
+  euro_countries <- c("AUT", "BEL", "HRV", "CYP", "EST", "FIN", "FRA", "DEU", "GRC", "IRL",
+                      "ITA", "LVA", "LTU", "LUX", "NLD", "PRT", "SVK", "SVN", "ESP")
+
+  my_countries <- country_base_years %>%
+    dplyr::filter(year == year_USMER, iso3c %in% euro_countries) %>%
+    dplyr::pull(iso3c)
+
+  gdp_in <- wb_wdi %>%
+    dplyr::filter(iso3c %in% my_countries,
+                  !is.na(`GDP (constant LCU)`)) %>%
+    dplyr::select("iso3c", "year", "value" = tidyselect::matches(regex_var_USMER))
+
+  gdp_conv <- constant_EURO_2_constant_USMER(gdp_in, year_USMER, wb_wdi) %>%
+    dplyr::filter(!is.na(value))
+
+  gdp_out <- constant_LCU_2_constant_USMER(gdp_in, year_USMER, wb_wdi) %>%
+    dplyr::filter(!is.na(value))
+
+  for (country in unique(gdp_conv$iso3c)) {
+    expect_equal(gdp_conv %>% dplyr::filter(iso3c == country),
+                 gdp_out %>% dplyr::filter(iso3c == country),
+                 label = country)
+  }
+})
diff --git a/tests/testthat/test-composite_conversions.R b/tests/testthat/test-04_composite_conversions.R
similarity index 96%
rename from tests/testthat/test-composite_conversions.R
rename to tests/testthat/test-04_composite_conversions.R
index 6170d71..19c288b 100644
--- a/tests/testthat/test-composite_conversions.R
+++ b/tests/testthat/test-04_composite_conversions.R
@@ -5,7 +5,7 @@
 
 test_that("current_LCU_2_constant_IntPPP_base_y", {
   gdp_in <- wb_wdi %>%
-    dplyr::filter(dplyr::if_all(tidyselect::matches(regex_var_IntPPP), ~!is.na(.x))) %>%
+    dplyr::filter(!is.na(!!rlang::sym(var_IntPPP))) %>%
     dplyr::select("iso3c", "year", "value" = `GDP (current LCU)`)
 
   gdp_conv <- current_LCU_2_constant_IntPPP_base_y(gdp_in, year_IntPPP, wb_wdi) %>%
@@ -25,7 +25,7 @@ test_that("current_LCU_2_constant_IntPPP_base_y", {
 
 test_that("current_LCU_2_constant_USMER_base_y", {
   gdp_in <- wb_wdi %>%
-    dplyr::filter(dplyr::if_all(tidyselect::matches(regex_var_USMER), ~!is.na(.x))) %>%
+    dplyr::filter(!is.na(!!rlang::sym(var_USMER))) %>%
     dplyr::select("iso3c", "year", "value" = `GDP (current LCU)`)
 
   gdp_conv <- current_LCU_2_constant_USMER_base_y(gdp_in, year_USMER, wb_wdi)%>%
@@ -119,7 +119,7 @@ test_that("current_IntPPP_2_constant_LCU_base_y", {
 
 test_that("current_IntPPP_2_constant_IntPPP", {
   gdp_in <- wb_wdi %>%
-    dplyr::filter(dplyr::if_all(tidyselect::matches(regex_var_IntPPP), ~!is.na(.x))) %>%
+    dplyr::filter(!is.na(!!rlang::sym(var_IntPPP))) %>%
     # Convert the PPP current series from one based on the linked LCU series
     # to one based on the standard LCU series
     dplyr::mutate(value = `GDP, PPP (current international $)` *
@@ -145,7 +145,7 @@ test_that("current_IntPPP_2_constant_IntPPP", {
 
 test_that("current_IntPPP_2_constant_USMER", {
   gdp_in <- wb_wdi %>%
-    dplyr::filter(dplyr::if_all(tidyselect::matches(regex_var_USMER), ~!is.na(.x)))  %>%
+    dplyr::filter(!is.na(!!rlang::sym(var_USMER))) %>%
     # Convert the PPP current series from one based on the linked LCU series
     # to one based on the standard LCU series
     dplyr::mutate(value = `GDP, PPP (current international $)` *
@@ -201,7 +201,7 @@ test_that("current_USMER_2_current_IntPPP", {
 
 test_that("current_USMER_2_constant_USMER", {
   gdp_in <- wb_wdi %>%
-    dplyr::filter(dplyr::if_all(tidyselect::matches(regex_var_USMER), ~!is.na(.x))) %>%
+    dplyr::filter(!is.na(!!rlang::sym(var_USMER))) %>%
     dplyr::select("iso3c", "year", "value" = `GDP (current US$)`)
 
   gdp_conv <- current_USMER_2_constant_USMER_base_y(gdp_in, year_USMER, wb_wdi) %>%
@@ -220,7 +220,7 @@ test_that("current_USMER_2_constant_USMER", {
 
 test_that("current_USMER_2_constant_IntPPP", {
   gdp_in <- wb_wdi %>%
-    dplyr::filter(dplyr::if_all(tidyselect::matches(regex_var_IntPPP), ~!is.na(.x))) %>%
+    dplyr::filter(!is.na(!!rlang::sym(var_IntPPP))) %>%
     dplyr::select("iso3c", "year", "value" = `GDP (current US$)`)
 
   gdp_conv <- current_USMER_2_constant_IntPPP_base_y(gdp_in, year_IntPPP, wb_wdi) %>%
@@ -343,7 +343,7 @@ test_that("constant_LCU_base_x_2_constant_IntPPP_base_y", {
 
     gdp_in <- wb_wdi %>%
       dplyr::filter(iso3c %in% my_countries,
-                    dplyr::if_all(tidyselect::matches(regex_var_IntPPP), ~!is.na(.x))) %>%
+                    !is.na(!!rlang::sym(var_IntPPP))) %>%
       dplyr::select("iso3c", "year", "value" = `GDP (constant LCU)`)
 
     gdp_conv <- constant_LCU_base_x_2_constant_IntPPP_base_y(gdp_in, my_base_year, year_IntPPP, wb_wdi) %>%
@@ -380,7 +380,7 @@ test_that("constant_LCU_base_x_2_constant_USMER_base_y", {
 
     gdp_in <- wb_wdi %>%
       dplyr::filter(iso3c %in% my_countries,
-                    dplyr::if_all(tidyselect::matches(regex_var_USMER), ~!is.na(.x))) %>%
+                    !is.na(!!rlang::sym(var_USMER))) %>%
       dplyr::select("iso3c", "year", "value" = `GDP (constant LCU)`)
 
     gdp_conv <- constant_LCU_base_x_2_constant_USMER_base_y(gdp_in, my_base_year, year_USMER, wb_wdi) %>%
@@ -503,7 +503,7 @@ test_that("constant_IntPPP_base_x_2_constant_LCU_base_y", {
 
 test_that("constant_IntPPP_base_x_2_constant_USMER_base_y", {
   gdp_in <- wb_wdi %>%
-    dplyr::filter(dplyr::if_all(tidyselect::matches(regex_var_USMER), ~!is.na(.x))) %>%
+    dplyr::filter(!is.na(!!rlang::sym(var_USMER))) %>%
     dplyr::select("iso3c", "year", "value" = tidyselect::matches(regex_var_IntPPP))
 
   gdp_conv <- constant_IntPPP_base_x_2_constant_USMER_base_y(gdp_in, year_IntPPP, year_USMER, wb_wdi)%>%
@@ -593,7 +593,7 @@ test_that("constant_USMER_base_x_2_current_USMER", {
 
 test_that("constant_USMER_base_x_2_constant_IntPPP_base_y", {
   gdp_in <- wb_wdi %>%
-    dplyr::filter(dplyr::if_all(tidyselect::matches(regex_var_IntPPP), ~!is.na(.x))) %>%
+    dplyr::filter(!is.na(!!rlang::sym(var_IntPPP))) %>%
     dplyr::select("iso3c", "year", "value" = tidyselect::matches(regex_var_USMER))
 
   gdp_conv <- constant_USMER_base_x_2_constant_IntPPP_base_y(gdp_in, year_USMER, year_IntPPP, wb_wdi)%>%
diff --git a/tests/testthat/test-convertGDP.R b/tests/testthat/test-05_convertGDP.R
similarity index 91%
rename from tests/testthat/test-convertGDP.R
rename to tests/testthat/test-05_convertGDP.R
index 4035b24..f64fb26 100644
--- a/tests/testthat/test-convertGDP.R
+++ b/tests/testthat/test-05_convertGDP.R
@@ -1,6 +1,7 @@
 test_that("convertGDP", {
   gdp_in <- wb_wdi %>%
-    dplyr::filter(!is.na(`GDP, PPP (constant 2017 international $)`)) %>%
+    dplyr::filter(!iso3c %in% bad_countries,
+                  !is.na(`GDP, PPP (constant 2017 international $)`)) %>%
     dplyr::select("iso3c", "year", "value" = `GDP (current LCU)`)
 
   gdp_conv <- convertGDP(gdp_in, "current LCU", "constant 2017 Int$PPP") %>%
@@ -15,12 +16,14 @@ test_that("convertGDP", {
 
 test_that("convertGDP different column names", {
   gdp_in1 <- wb_wdi %>%
-    dplyr::filter(!is.na(`GDP, PPP (constant 2017 international $)`)) %>%
+    dplyr::filter(!iso3c %in% bad_countries,
+                  !is.na(`GDP, PPP (constant 2017 international $)`)) %>%
     dplyr::select("r"=iso3c, year, "value" = `GDP (current LCU)`)
   gdp_in1b <- dplyr::mutate(gdp_in1, r = "")
 
   gdp_in2 <- wb_wdi %>%
-    dplyr::filter(!is.na(`GDP, PPP (constant 2017 international $)`)) %>%
+    dplyr::filter(!iso3c %in% bad_countries,
+                  !is.na(`GDP, PPP (constant 2017 international $)`)) %>%
     dplyr::select(iso3c, "y" = year, "value" = `GDP (current LCU)`)
   gdp_in2b <- dplyr::mutate(gdp_in2, y = "")
 
@@ -65,7 +68,7 @@ test_that("convertGDP magpie object", {
                                  years = c(2001, 2002),
                                  names = c("ssp1", "ssp2"),
                                  fill = 100)
-  magclass::getSets(gdp_in)[1] <- c("r")
+  magclass::getSets(gdp_in)[1] <- c("iso3c")
 
   gdp_conv <- convertGDP(gdp_in, "current LCU", "constant 2017 Int$PPP")
 
@@ -86,7 +89,8 @@ test_that("convertGDP data.frame object", {
 
 test_that("convertGDP unit_in == unit_out", {
   gdp_in <- wb_wdi %>%
-    dplyr::filter(!is.na(`GDP, PPP (constant 2017 international $)`)) %>%
+    dplyr::filter(!iso3c %in% bad_countries,
+                  !is.na(`GDP, PPP (constant 2017 international $)`)) %>%
     dplyr::select(iso3c, year, "value" = `GDP: linked series (current LCU)`)
 
   expect_message(convertGDP(gdp_in, "current LCU", "current LCU", verbose = TRUE),
diff --git a/tests/testthat/test-replace_NAs.R b/tests/testthat/test-06_replace_NAs.R
similarity index 86%
rename from tests/testthat/test-replace_NAs.R
rename to tests/testthat/test-06_replace_NAs.R
index 165cba8..80c1d0b 100644
--- a/tests/testthat/test-replace_NAs.R
+++ b/tests/testthat/test-06_replace_NAs.R
@@ -55,27 +55,27 @@ test_that("convertGDP replace missing conversion factors", {
 })
 
 test_that("convertGDP replace_NAs = NA", {
-  # wb_wi does not have info for ABW in 2019
-  gdp <- tidyr::expand_grid("iso3c" = c("ABW", "DEU", "USA"),
+  # wb_wi does not have info for AFG in 2022
+  gdp <- tidyr::expand_grid("iso3c" = c("AFG", "DEU", "USA"),
                             "year" = c(2010, 2015, 2025),
                             "SSP" = c("SSP1", "SSP2"), "value" = 100)
 
   expect_warning(convertGDP(gdp,
                             unit_in = "constant 2005 Int$PPP",
-                            unit_out = "constant 2019 US$MER"))
+                            unit_out = "constant 2022 US$MER"))
 
   expect_silent(convertGDP(gdp,
                            unit_in = "constant 2005 Int$PPP",
-                           unit_out = "constant 2019 US$MER",
+                           unit_out = "constant 2022 US$MER",
                            replace_NAs = NA))
 
   gdp_1 <- suppressWarnings(convertGDP(gdp,
                                        unit_in = "constant 2005 Int$PPP",
-                                       unit_out = "constant 2019 US$MER"))
+                                       unit_out = "constant 2022 US$MER"))
 
   gdp_2 <- convertGDP(gdp,
                       unit_in = "constant 2005 Int$PPP",
-                      unit_out = "constant 2019 US$MER",
+                      unit_out = "constant 2022 US$MER",
                       replace_NAs = NA)
 
   expect_equal(gdp_1, gdp_2)
@@ -83,36 +83,36 @@ test_that("convertGDP replace_NAs = NA", {
 
 
 test_that("convertGDP replace_NAs = 'no_conversion'", {
-  # wb_wi does not have info for ABW in 2019
-  gdp <- tidyr::expand_grid("iso3c" = c("ABW", "DEU", "USA"),
+  # wb_wi does not have info for AFG in 2022
+  gdp <- tidyr::expand_grid("iso3c" = c("AFG", "DEU", "USA"),
                             "year" = c(2010, 2015, 2025),
                             "SSP" = c("SSP1", "SSP2"), "value" = 100)
 
   expect_warning(convertGDP(gdp,
                             unit_in = "constant 2005 Int$PPP",
-                            unit_out = "constant 2019 US$MER"))
+                            unit_out = "constant 2022 US$MER"))
 
   gdp_conv <- convertGDP(gdp,
                          unit_in = "constant 2005 Int$PPP",
-                         unit_out = "constant 2019 US$MER",
+                         unit_out = "constant 2022 US$MER",
                          replace_NAs = "no_conversion")
 
   expect_identical(gdp[1:6,], gdp_conv[1:6,])
 })
 
 test_that("convertGDP replace_NAs = linear", {
-  # wb_wi does not have info for ABW in 2019
-  gdp <- tidyr::expand_grid("iso3c" = c("ABW", "DEU", "USA"),
+  # wb_wi does not have info for AFG in 2022
+  gdp <- tidyr::expand_grid("iso3c" = c("AFG", "DEU", "USA"),
                             "year" = c(2010, 2015, 2025),
                             "SSP" = c("SSP1", "SSP2"), "value" = 100)
 
   expect_warning(convertGDP(gdp,
                             unit_in = "constant 2005 Int$PPP",
-                            unit_out = "constant 2019 US$MER"))
+                            unit_out = "constant 2022 US$MER"))
 
   gdp_conv <- convertGDP(gdp,
                           unit_in = "constant 2005 Int$PPP",
-                          unit_out = "constant 2019 US$MER",
+                          unit_out = "constant 2022 US$MER",
                           replace_NAs = "linear")
 
   expect_true(!any(is.na(gdp_conv$value)))
diff --git a/tests/testthat/test-verbose.R b/tests/testthat/test-07_verbose.R
similarity index 100%
rename from tests/testthat/test-verbose.R
rename to tests/testthat/test-07_verbose.R
diff --git a/tests/testthat/test-warn.R b/tests/testthat/test-08_warn.R
similarity index 100%
rename from tests/testthat/test-warn.R
rename to tests/testthat/test-08_warn.R
diff --git a/tests/testthat/test-get_conversion_factors.R b/tests/testthat/test-09_get_conversion_factors.R
similarity index 100%
rename from tests/testthat/test-get_conversion_factors.R
rename to tests/testthat/test-09_get_conversion_factors.R
diff --git a/tests/testthat/test-print_source_info.R b/tests/testthat/test-10_print_source_info.R
similarity index 71%
rename from tests/testthat/test-print_source_info.R
rename to tests/testthat/test-10_print_source_info.R
index 609ac44..0d64847 100644
--- a/tests/testthat/test-print_source_info.R
+++ b/tests/testthat/test-10_print_source_info.R
@@ -3,7 +3,9 @@ test_that("multiplication works", {
   expect_message(
     expect_message(
       expect_message(
-         print_source_info()
+        expect_message(
+          print_source_info()
+        )
       )
     )
   )