The Energy Department says U.S. households spent an average of $2,912 on gasoline, or almost 4 percent of their pretax income, the highest percentage in 30 years.
That's despite the fact that Americans consumed less fuel in 2012 for a variety of reasons, including more efficient driving habits and higher-mileage vehicles.
"The effect of the higher prices in 2011 and 2012 outweighed the effect of reduced consumption," the Energy Department said.
In fact, researchers at the University of Michigan said Monday that the average fuel economy for new vehicles sold in the U.S. reached a record 24.5 mpg in January -- up 0.4 mpg from a revised figure for December.
Meanwhile, the Union of Concerned Scientists reported that most Americans "are likely to spend almost as much on gasoline over the life of their vehicle as its original cost."
"You're basically paying for a second car every 15 years. The only thing really benefiting from your oil use is oil companies' bottom line," said Joshua Goldman, the report's author and a policy analyst for the advocacy group.