Interesting that R looks late to the party with the highest growth rate over this period - I find it doubtful that R has grown so much in that time, but I guess

Interesting that R looks late to the party with the highest growth rate over this period - I find it doubtful that R has grown so much in that time, but I guess instead that academic coders have started to use Github. Does this suggest that R usage is greatly underestimated, generally, then? Also why did all of Perl get pushed in Q3/12? And every language got a significant peak that quarter? Is that a data error?