WASHINGTON (AP) – Oil prices fell below $74 a barrel Wednesday after the U.S. government released data showing that gasoline demand has been flat over the past four weeks and that motor fuel supplies are growing as refineries ramp up output.

But a high floor persists underneath oil prices amid nagging concern that Iran, a key exporter, could cut supplies because of international pressure to modify its nuclear program. Strong global demand, unrest in Nigeria and concerns about the next Gulf of Mexico hurricane season have also exerted upward pressure on prices.

Light, sweet crude for June delivery fell $1.01 to $73.60 a barrel on the New York Mercantile Exchange. A peak of $75.35 was reached April 21.

The decline in crude followed a sharp drop in gasoline futures, which sank 4.26 cents to $2.13 a gallon.

Pump prices in the U.S. average $2.92 a gallon, or 30 percent more than a year ago. And there is evidence that these high prices may be suppressing demand at the margins.

Over the past four weeks, average daily gasoline demand in the U.S. was 9.127 million barrels per day, barely higher than year-ago demand of 9.125 million barrels a day, according to the Energy Department. And since the start of the year, average daily gasoline demand has been just a hair over 9 million barrels per day, slightly below last year.

In its weekly report, the agency also said that:

• Domestic inventories of gasoline climbed by 2.1 million barrels, reversing eight straight weeks of declines. U.S. gasoline supplies stand at 202.7 million barrels, or 5 percent below year ago levels.

• Refineries ran their plants at 88.8 percent of capacity, compared with 88.2 percent a week earlier.

• Crude oil inventories climbed by 1.7 million barrels to 346.7 million barrels, or roughly 5 percent above year ago levels; the supply of distillate fuel, which includes heating oil and diesel, fell by 1.1 million barrels to 114.5 million barrels, but is almost 10 percent above last year.

Still, crude oil prices are about 40 percent higher than a year ago as a result of geopolitical tensions that are not likely to ease soon, analysts said.

“Political tensions in Iran, a refinery outage in Italy and supply disruptions in Africa (are) keeping the bulls running towards record values,” said Vienna’s PVM Oil Associates, predicting near-term price increases. PVM also said that investments by hedge funds, pension funds and other investors seeking to cash in on rising energy prices were also creating a self-fulfilling prophecy. PVM noted reports that America’s biggest pension fund, the California Public Employees’ Retirement System, planned to allocate as much as $1 billion into oil and other commodities by August.

But Iran continued to occupy center stage.

On Tuesday, an Iranian official reiterated the country’s intention to keep enriching uranium, while U.S. Undersecretary of State Nicholas Burns said he believed European governments will agree to sanctions against Iran.

The United States, Britain and France plan to introduce a new Security Council resolution this week that would make Iran’s compliance with their demands mandatory, and enforceable through sanctions or military action.

As of yet, there has been no talk of economic sanctions that could slow Iran’s oil exports. China is a big customer for Iranian oil, and a cutoff of its oil exports would likely send oil prices surging.

In other Nymex prices Wednesday, natural gas fell 3.1 cents to $6.715 per 1,000 cubic feet.

Brent crude fell 68 cents to $73.96 a barrel on the London’s ICE Futures exchange, below its intraday record of $74.97.