The count of contributions (summary of Pull Requests, opened issues and commits) to public repos at GitHub.com from Wed, 29 Jul 2015 01:52:41 GMT till Fri, 29 Jul 2016 01:52:41 GMT.
Only first 1000 GitHub users according to the count of followers are taken. This is because of limitations of GitHub search. Sorting algo in pseudocode:
githubUsers
.filter(user => user.followers > 6)