What do the Boston Celtics, Houston Rockets and San Antonio Spurs have in common? Yes, they all made it deep into the playoffs last season. Yes, they all have multiple NBA Championships. And, Yes, they are all internationally popular. But, what you probably didn’t guess is that all three of those franchises had lower overall attendance than the 23-game winning Oklahoma City Thunder during the 2008-09 season. The Thunder averaged close to 19,000 fans per game, which is 97.7 percent of total ca...