[mneil]

While not definitive github does an annual "state of" report. Other sites do this as well and they often show trends in languages; although none of the other reports are top of mind for me right now.

https://octoverse.github.com

[mtmail]

https://insights.stackoverflow.com/survey/2017#technology-fr... is another notable one.

[samueldavid]

thanks, but currently I'm more interested into which are more in demand or used on the remote market, those sites included both on site and remote, but not remote only.