Quarterly Peak Consumption was Q3 2005 - 4,067,963,214. Q3 2011 gasoline consumption - 3,727,070,122, which was slightly lower than the 2009 Q3 in the midst of the Great Recession.
2005 was the peak year - 15,937,855,020. 2011 consumption will certainly come in lower than 2010's consumption of 14,868,892,787.
Keep in mind that U.S. gasoline "supply" increased by nearly 10% with the development of corn ethanol. Said another way, absent ethanol, the supply/consumption of gasoline decline would have been closer to (just under) 4% than (just under) 2%. But ethanol was a one off... there is no 880,000 bpd increase in ethanol available to the market over the next 6 or 7 years as there was in the previous 6 or 7. That does not assure an increase in the decline rate... but it certainly increases the likelihood.
If Peak Oil has not hit the world, it sure seems to have hit California's gasoline supply... and California is home to 1 out of every 8 Americans... likely a large enough sampling to be applied to the U.S. as a whole.
This is not the only thing wrong with the U.S. (and the other industrialized nations) economy... but its a biggee.