Simple - depends on the boxer. Joichiro Tatsuyoshi had 19 amateur bouts in the space of one year, at 18 years old. He won the World Championship in his 8th pro bout, against a solid and very experienced world champion shortly afterward, destroying him. Meanwhile, there are guys who have hundreds of bouts who, maybe, become Euro level at their highest. Nothing wrong with that, but even with 100+ bouts they'll never be a super talent like Joe.
