Since 2000 their have been 116 hirings and firings of NFL head coaches - 38 of those have been “retread” head coaches (32.8%), meaning that they have been a head coach (not just interim) before in the NFL. That number is lower than I would have expected since it seems that the NFL keeps bringing around the same few tired head coaches and giving them one more shot. What this also means is that 78 of the head coaches hired this century in the NFL had zero NFL head coaching experience when they were hired (67.8%).
Why is the relevant?