StackOverflow - Number of Perl questions by month

I began to collect Perl Stack Overflow data three years ago. I have just plotted a graph with the number of questions grouped by month. According to these data, it seems we have reached the maximum activity last year.

Perl questions created by month, from 2011/11 to 2014/10

And this was the most voted Perl question on that period of time:
Why is this program valid? I was trying to create a syntax error