Last year Gabor Hojtsy posted on Drupal's development mailing list about Ohloh, a site that inspects and reports Open Source software projects.
Since then, Drupal core has been split off, with the core committers only showing. The interesting part is user jeroen, who is no longer active (at least not under that name), and anonymous has one stray commit for some reason. Also see Steven Wittens (unconed) comments on Drupal core composition.
Now, Drupal contrib is its own project, there are interesting observations too.
The obvious people are there: including long timers such as Gerhard Killesreiter (killes), Moshe Weitzman (moshe) and Gordon Heydon (gordon). Relatively new people who are prolific include Derek Wright (dww), and Earl Miles (merlinofchaos).
Some currently inactive users include mathias with 530 commits, but almost none for the last 2 years.
There are 809 total contributors.
At number 10, there is me (kbahey), with 527 commits over 2.7 years (although I started with Drupal almost 4 years ago this summer). The Kudo Rank of 8 (whatever that means).
Here is a screenshot: