Too many variables to identify any means of a conclusive average.
I've never inflated my distance, for two reasons... one - why would I brag about hitting the ball 30 yards further, knowing that I occasionally play with some guys here who read my posts?! LOL
Secondly - as much as I'd love another 20-30 yards off the tee, distance really isn't holding my game back, at least based on the preferred tee boxes I tend to play. If you put me back to 6800 yards, then certainly... I'm gonna be hitting lumber into a lot of greens, and that's in no way shape or form something I'd enjoy anymore. Maybe 10 years ago I could've managed it. Of course - 10 years ago I was hitting the ball 20 yards further too.
Once you figure in overall athleticism, flexibility, age, technique, playing level, height and body build, frequency of play, etc. it becomes futile to attempt to base an average distance on some sort of reliable metric. Too many variables.