Pure-python modules are not CPython modules.
But indeed statistics is bundled with Rhino.
@Joseph_Oster Why this increasing slowness happens is a mystery indeed. My best guess is something in the statistics module and/or its dependencies cause IronPython to do weird things. Maybe in combination with how perhaps tree is automagically chopped into its branches for list access (lots of New Implicit Grasshopper Cycles messages in script window output pane). But instead of wasting time into IronPython or the statistics and dependant modules:
Here is a simple Python implementation that should work just fine
statistics_2023Feb25a.gh (14.0 KB)