Does this data have anything to do with anything? Because these appear to be percentages of jobs on indexed job sites that mention term X, every single program

Does this data have anything to do with anything? Because these appear to be percentages of jobs on indexed job sites that mention term X, every single programming language that I checked is shrinking in share. Is that because software is becoming passé? Is it because there's a sudden enormous demand for pipefitters? Or is it just because some hiring managers (but not others) have concluded that hiring people through job site postings is a complete waste of time? And is the relative share of Java, C++, Perl, Ruby, and Python being completely skewed by the relative percentages of hiring managers who think that job sites are a complete waste of time? I certainly would never make an open job posting for a Ruby programmer unless I had no other choice. I don't enjoy reading resumés with a shovel.