[theme-reviewers] Most Popular download counts seems off

[Otto]

The most popular list on the main page shows a revolving count over
the last two weeks (roughly). This is to keep the list changing as
trends change. If we just used the total count or something like that,
then one could go to the top and stay there.

The numbers are correct, just not obvious as to what it is that
they're counting. :)

-Otto