Maybe this is a general time trend for many languages not just Haskell. Also, the real question is what percentage of jobs are Haskell related.
Absolute number and percentage are both interesting metrics depending on what you are interested in.
"Robert and I both knew Lisp well, and we couldn't see any reason not to trust our instincts and go with Lisp. We knew that everyone else was writing their software in C++ or Perl. But we also knew that that didn't mean anything. If you chose technology that way, you'd be running Windows. When you choose technology, you have to ignore what other people are doing, and consider only what will work the best."
E.g. even if "getting your face hit by a brick, hourly" is a more widely demanded skill and has more job openings than Haskell I'd still pick the latter.