(79,80,81)
Few pitchers are throwing this hard on any high-school team, the best are throwing 85 and there is a big drop off after taht i would say the average is around (72 or 73). Remember average is everyone, I'd say in the eighties if you have any ambition to go anywhere, scouts need to see some velocity. The thinking is that you can teach movement but you can't teach someone to throw that hard. Plus most pitching coaches can add five to ten MPH to your fastball the next stage is getting good movement. So John J your wrong but you are right in the aspect that anyone with a chance of moving on averages about that.
Hope This Helped!!!
P.S.----One of the best pitches in baseball, SPLITTER!!! Throw it, use a softball to stretch ur ligaments then find the grip on the ball for more info just ask!