This IEEE survey, based on code available in various repositories, concludes that Java is (by a short margin) the most popular language occurring in these sources. If you had expected choices such as Ruby and Objective C to be front runners, then you may be surprised to find that overall, the list of top languages has a distinctly "old school" feel to it: C is a close second to Java, followed by C++ and C#. Objective-C comes a distinctly underwhelming 16th.
We will avoid a debate here (but the article comments needless to say have not) around whether choices such as "HTML", "MATLAB" and "R" count as programming languages.
Of course, the choice of languages reflects the specifically the choice of languages occurring in code repositories rather than the interest in these languages across the industry as a whole. It's frankly improbable that there are more MATLAB programmers than iOS and Mac OS programmers and the vast majority of programmers in the universe have probably never even heard of R. What I suspect this graph is showing us to a large extent is the relative proportion of programmers in various languages who share their code in repositories versus those who keep it under their hat.
Still, for those of us who started learning to program in the 80s, it does seem to indicate that our trusty C skills are not going to be obsolete any time soon... :)