Here is an older post that I found using the Search function.
http://community.hsbaseballweb...0-mph-bat-exit-speed
I like that they were measuring exit speed, however, this was in BP off of BP pitching.
So the exit speeds will be higher off of a pitched ball than off a tee according to info in the link provided by
Bolts-Coach-PR: http://www.efastball.com/hitti...-speed-by-age-group/
How much faster, I don't know. It's all relative to the pitch speed.