The NFL was formed in 1920 as the American Professional Football Association (APFA) before renaming itself the National Football League for the 1922 season. The NFL agreed to merge with the American Football League (AFL) in 1966, and the first Super Bowl was held at the end of that season; the merger was completed in 1970. Today, the NFL has the highest average attendance (67,591) of any professional sports league in the world[4] and is the most popular sports league in the United States.[5] The Super Bowl is among the biggest club sporting events in the world[6] and individual Super Bowl games account for many of the most watched television programs in American history, all occupying the Nielsen's Top 5 tally of the all-time most watched U.S. television broadcasts by 2015.[7] The NFL's executive officer is the commissioner, who has broad authority in governing the league. The players in the league belong to the National Football League Players Association.