Bloomberg's numbers use the Energy Department's monthly average price that refineries pay for imported oil, adjusted to reflect data on disposable income from the Commerce Department's Bureau of Economic Analysis.
Even taking into account population growth, oil is cheaper today than it was three decades ago. Adjusted for per capita disposable income, prices peaked at $156 in January 1981.
"The income factor does play a role" in absorbing rising oil prices, said Sander Cohan, a principle at Energy Security Analysis Inc. in Wakefield, Massachusetts. "The reaction to higher energy prices is always a move toward efficiency."
Unadjusted nominal import prices started to rise in 1979 to peak at $39 a barrel in February 1981, more than doubling from the $14.9 level of December 1978.
The Iranian Revolution, which began in late 1978, resulted in a drop in Iran's oil production of 3.9 million barrels per day from 1978 to 1981, according to the Energy Department. That's about 6.4 percent of 1981's world oil production, standing at 60.6 million barrels a day, department data showed.
Production dropped further during the Iran-Iraq War, which started in 1980. By the following year output from the Organization of Petroleum Exporting Countries declined to 22.8 million barrels per day, 7 million barrels below its level for 1978, according to the department.
This year's rise in global oil costs "is likely to push up inflation temporarily while reducing consumers' purchasing power," Fed Chairman Ben S. Bernanke said in semi-annual testimony to Congress on March 1. He also said policy makers expect inflation will remain "subdued."
Gasoline's gains are pinching Americans' pockets just as the economy is gaining momentum, according to Neil Dutta, an economist at Bank of America Corp. in New York. The increase in fuel costs may trim as much as half a percentage point from U.S. economic growth, he said.
"The gas price story is damping growth prospects," he said. "The economy is in a better place than last year, but it isn't materially better. The increase in energy prices is a significant headwind."