This library allows to build lossy histograms online and then to estimate how many values live in a given interval. It's based on the paper A Streaming Parallel Decision Tree Algorithm
There are two variants of streaming libraries: Bounded by memory and bounded by accuracy. This library is bounded by memory. According to the authors this library is senstive to skewed distributions but I haven't tried yet.
NB This library is really inefficient and probably bad Haskell because it is my first ever Haskell release.