Github has posted an article on the popularity tends for languages on Github since 2008:
Whats most interesting is that PHP has remained consistent throughout the chart no movement in either direction. As with all languages users come and go but not all users are using Github still I am surprised it’s so steady. I’m not surprised in the increase of Java with the popularity of Android. Also no suprise with JavaScript either that’s to be expected. There are new frameworks and JS based tools being released at an increasingly fast pace.