When the Philadelphia Eagles dismissed Andy Reid earlier this month, it made the Patriots’ Bill Belichick the longest-tenured head coach in the NFL.

Between the day Belichick was hired, Jan. 27, 2000, and the end of the 2012 season, 127 different head coaches served on the other 31 teams in the NFL. Among the teams with the most instability at head coach are the Raiders (eight) and the Dolphins, Redskins, and Lions (seven each). The 127 coaches represents an average of just more than four per team.