There have been a finite number of jobs advertised, right? You must be able to average *those*.

Well, sure, but that's only a statistical sample and its mean will be at best an approximation to the mean of the real distribution. In this case, a very bad approximation!

Besides, yours has a perfectly good mode and median :)

That is true. I could at least have arranged for it to be bimodal. However, it's rather difficult to avoid having a median...