Given that there are only 7.5 billion humans on the planet, and that rather significantly fewer than 1 in 20 people are PyPy-using developers, perhaps those numbers should be taken with a grain of salt?

The message I would take from those statistics is that needing a fresh download of Pypy is less common among 3.x users than among 2.7 users, who apparently needed to reinstall from the web at least a few times a day during 2016.

A huge confounding factor: newer Py3 codebases are more likely to be built with newer pipeline tooling like devpi (to cache PyPI downloads), wheel (to cache locally-built packages), and Docker (which caches all the things).

Our legacy Python 2 build pipelines that we're actively moving off of hit PyPI far more often than our Py3 processes.

The PyPy statistics aren't worth much since they're counting all sorts of automated downloads/dependencies/etc.

That's why packages like supervisor and graphite - which aren't libraries - are among the top downloads.