What a coworker did when he was starting college back some decades, he asked where all the COBOL jobs were, the teacher got very angry, so he dropped out and went to a different university, where they were teaching Delphi / VB which definitely had a better job market. So you might never have a "perfect" number, but at least locally, you can kind of figure out what local employers are hiring for, which is usually what you'd care most about anyway. I think we've reached a point where unless you're doing something specialized, for the most part programming language choice is about developer familiarity these days.
