Here's how the 2012 NBA Finals lined up with the previous six:
2012 represented yet another step up for the NBA as this time they got a fairly attractive opponent to go up against LeBron James' Heat. The games went 6.9 -> 7.1 -> 6.5 -> 7.4 -> 7.6. Most games were up 5-10% year-to-year. An ABC presser said this series had the highest ratings through five games since 2004, and most games in this series (1, 4, 5) were the biggest for those individual games since 2004. Game 2 was actually higher than its 2004 counterpart (7.1 vs. 7.0) and the biggest since 2001, while Game 3 was the only one to finish behind a corresponding game on this chart.
However, the series did not take off to nearly the extent of the five-game series in 2004 (which skyrocketed from 7's in the first three games up to 9.1 and 9.4 for the last two). And the relatively short length of the series prevented it from reaching the heights of the last two seasons. There was not that much of a spike in the decisive fifth game, thanks to a blowout and perhaps some Heat hate. Only 3% more adults 18-49 on average watched that game vs. the previous one, compared to the 31% who showed up for the Heat's elimination in Game 6 the prior year. And despite the elimination, which usually helps, Game 5 was up the least year-to-year of any of the five games (just +3%).