IIRC the guy who wrote this article http://redmonk.com/dberkholz/2014/05/02/github-language-tren... about GitHub language trends scraped the numbers from the search page, e.g. the following search yields all repos created in 2014 and the language breakdown in the sidebar: https://github.com/search?utf8=%E2%9C%93&q=created%3A%22%3E%...