An average of 4.5 QBs per year become first time starters in the NFL. Meaning they start at least one game at some point. Since Heupel started coaching QB's that were draft eligible (2010) that would mean 67 new QBs have gotten a starting opportunity. Sam Bradford, Dillon Gabriel, Joe Milton, Drew Lock, and Landry Jones have all started games. So, he has coached 7.5% of all new starters since becoming a coach. I can't imagine who has coached more.