I came of running age as a college walk on in the early 90s and we probably raced 25 times per season or more (including cross country, indoor and outdoor).
The trend today at the college level is obviously to race less often than that, and think most post-collegians race a lot less often than that because they have other things going on and because of the more challenging logistics and increased expense of racing as compared to college.
That leads me to wonder how often post-collegians race. For me it is about 10-12 times per year.