The list has data bias. Number of downloads of a plugin per day as the measure of popularity is faulty.

Check today’s list and you will see that the top plugins(atleast the first few) are the one which had a new update recently.

I had done something similar for my research a few months ago and that revealed a lot about the repository.

A better measure of popularity should be an average over a span of time and with some bias for the number of updates during that period.