While this comes up every single time somebody talks about functional programming making inroads, I still consider it a fairly unhelpful indicator. First, nobody's arguing that big companies are suddenly doing the bulk of their development in these languages. It's about using them at all. Second, job postings may be lagging and distorted in their own way (e.g., junior positions are much more likely to be publicly advertised, and so on).

The less said about TIOBE, the better.