The National Football League (NFL) is a professional American football league consisting of 32 teams, divided equally between the National Football Conference (NFC) and the American Football Conference (AFC). The NFL is one of the four major North American professional sports leagues, the highest professional level of American football in the world, the wealthiest professional sport league by revenue, and the sport league with the most valuable teams. Today, the NFL has the highest average attendance (67,591) of any professional sports league in the world and is the most popular sports league in the United States. The Super Bowl is also among the biggest club sporting events in the world, with the individual games accounting for many of the most watched television programs in American history and all occupying the Nielsen's Top 5 tally of the all-time most watched U.S. television broadcasts by 2015. The Green Bay Packers hold the most combined NFL championships with 13, winning nine titles before the Super Bowl era and four Super Bowls afterwards. Since the creation of the Super Bowl, the Pittsburgh Steelers and New England Patriots both have the most championship titles at six.