And those who live aboard or who are able to do extended cruising also skew the numbers a bit. That said, I seem to recall reading a report from BoatUS at some point that said the average usage is 50-100 hours per year, although I just tried to find it on the website and no luck. I still think this group well exceeds that average.
Oh, I don't expect these numbers to reflect the average boat owner. We are a narrower demographic. The 50-100 hours for the average is what I've heard and believe as well. That number's a little high even as you have so many who barely use it. I've known boat owners who used it one week a year. I knew people who lived on the lake and would take perhaps a 2 hour ride every other week during warm weathy. They'd use it less than 25 hours.