You cannot compare just 2010 to 2011. For an accurate picture, go back the last five seasons prior to 2011 and you will get a more accurate picture. Youmust also take into account, summer of 2011 set several records around the country for heat and humidity. Not saying you are not right but by far, comparing only one preceding season will not give you an accurate picture.
OK, I added data for the last 5 years. It still supports my argument that something was clearly off with the defenses across the league.
2011:
Games where both teams scored more than 20 points: 6
Games where at least one team scored more than 20 points: 15
Games where at least one team scored more than 30 points: 8
Games where both teams scored less than 20 points: 1
2010:
Games where both teams scored more than 20 points: 3
Games where at least one team scored more than 20 points: 8
Games where at least one team scored more than 30 points: 4
Games where both teams scored less than 20 points: 8
2009:
Games where both teams scored more than 20 points: 6
Games where at least one team scored more than 20 points: 12
Games where at least one team scored more than 30 points: 4
Games where both teams scored less than 20 points: 4
2008:
Games where both teams scored more than 20 points: 3
Games where at least one team scored more than 20 points: 12
Games where at least one team scored more than 30 points: 5
Games where both teams scored less than 20 points: 4
2007:
Games where both teams scored more than 20 points: 3
Games where at least one team scored more than 20 points: 11
Games where at least one team scored more than 30 points: 5
Games where both teams scored less than 20 points: 5