While this a very good study, I am not sure that "average" is the statistic to use in this case.
You could have three 60 year olds and one 5 year old, with and average age of 46, but there were no 46 year olds present at all. The problem is the missing age brackets and the distribution, not the average age.
That's why Golden state is a good choice - there are so many entries that the anomalies have less effect on the results. But since I know for sure, there was a 7-year-old, the next youngest was 18, and everybody else was in their 20s or older. There were a bunch of people in their mid-20's-40, a few in the 40-50 range, and bunch over 50 and
65. That also makes some sense, the older people would have started when C/L was still pretty big (and R/C was expensive and unreliable), the 40-50s were around when it looked pretty bad in the late 70's-mid-80's, and the rest started after the real explosion in the late 80's and 90's. I would have to spend a little time to work it out better than that, and if I do, I will add the 2007 and 2008 NATs entries, and 2007 Golden State. But don't wait around for it, I got a lot of irons in the fire and anybody else could do something similar with the NATs, Brodak's contest (just stunt entries), or any other big conventional contest, and I think the answer will be about the same.
Brett
p.s. NATS 2004 Open entrants = avg age - 46.5 . And an observation - assuming a uniform distribution, and that on average people stop flying around 70, you would expect the average in Open to be around 45. So the two examples I have indicate that we are very close to the average age you would expect, not skewed towards oldsters. It's clear to me that it's not actually uniform, but "u"-shaped right now, but nonetheless...
I invite/suggest anyone interested to take the entry lists from big contests and, knowing who is who, guess the ages. Make fair guesses - don't intentionally guess to make your argument come out right. I have probably done all that I am going to, since I have pretty much convinced myself my gut feeling was about right. I did get a surprise about the distribution, but it makes sense in retrospect.