|May 18||May 19||May 20||May 21||May 22||May 23||May 24||Avg Growth|
|Maven Central (Java)||105738||105874||105933||106057||106163||106231||106351||102/day|
Data is collected by scraping the relevant websites once a day via a cron job and then stored in a Postgresql database for later retrieval. Growth rates are calculated by averaging data over the last week. I'm gathering counts of separate modules, so multiple versions of the same module/package/gem only count once (foo-1.2, foo-1.3 and bar-1.0 would count as 2 total).
(Feb 2, 2014) Upgraded off the free database plan. The database had outgrown Heroku's 100% free tier. It still qualifies for the hobby level, though. Also added the Melpa (Emacs) repository, and update the Hackage (Haskell) repository to use a different and hopefully more reliable data source.
(Mar 30, 2013) Several folks asked me to add Maven Central. It's a really big Java module repository. I look forward to seeing how fast it's growing. For now, this is the first time we've had a change in the top spot since Rubygems.org passed up CPAN in early 2011.
Several other folks reported issues with IE compatibility, CSV downloads and chart layout. Hopefully those are all fixed now.
I just (Nov 25, 2012) added the Clojars repository. Much thanks to Jonas Clasen for pointing it out to me.
CPAN and CPAN (search) used to be two conflicting sources for data about how many modules are in CPAN. During spring of 2011 CPAN got a site refresh and the numbers came into line with each other. It looks funny on the graph, but it's an interesting bit of history.
If you'd like to check out the data in more detail, you are welcome to download it in a CSV file.