Let’s see, there are roughly 1696 NFL players at a given time and 8470 NCAA Division 1A players (making some assumptions, including the assumption that all teams carry the maximum number of players). That would be 20%. But that’s not the right answer. We have to know how many players leave college in a given year, and how many new players enter the NFL in a given year. There are 384 draft picks in a given year. If a playing career in the NCAA is 5 years, then we can assume that 1/5 of NCAA players leave in a given year, so that’s 1694 players available. Assuming all of the NFL draft picks are new college “graduates”, then we’re still at about 20%. I think that’s still a high estimate. It doesn’t take into account the number of players drafted who will be cut and not signed by another team. Also, I think my number of NCAA Division 1A players per team may actually be low, depending on your definition of being a Division 1A player. OK, I did my best, I think we need more expertise here.