I read somewhere that the average man hits at around 100PSI, but the men tested were most likely the nerds in the office, so lets add another 100 or so to that.
I don't really trust a lot of the PSI tests to be honest. It all depends on angle and stuff. The Tyson PSI is a myth, I read they offered him to take one back when he was champ around 1987 or 1988, but Bill Cayton said no because there was no money involved and didn't want to risk hurting Mike's hand.
Back in the mid 60's some people tested an older, out of shape, Rocky Marciano with his power. They found out that his right hand had more force behind it than an armor peircing bullet, and that it got spot lift 1000lbs 12 inches off of the ground.