I found this an interesting article. It shows some trends that are expected, C going down in the past few years and Objective C. Perl took quiet a nosedive and seems to have fallen off. I was surprised at the jump in CSS. And Java too. I figured Python would have a jump up over Java. But instead Python went the other direction. Not too surprised by the drop in Ruby too.
http://www.wired.com/2015/08/github-data-shows-changing-software-landscape/