I see something I find interesting here: Toward the bottom of the page, it gives long-term history for some languages. In 1997, the rankings were C, Lisp (!), Prolog, and C++ in the top four. Lisp was #2, above C++.
Apparently Lisp was at one time much more popular (at least as measured by TIOBE - I know, their rankings may not correlate to reality...)