By far the most useful and helpful is job ads: it literally defines the demand side of the programming language market.
Yes, that does not show us how much code is running out there, and some companies might have huge armies with very low churn and so the COBOL stacks in banks don’t show up, but I can’t think of a more useful and directly measurable way of understanding a languages real utility.
Yes, that does not show us how much code is running out there, and some companies might have huge armies with very low churn and so the COBOL stacks in banks don’t show up, but I can’t think of a more useful and directly measurable way of understanding a languages real utility.