NEW YORK (Reuters) - The price of a gallon of gasoline in the United States rose 11.49 cents over the past two weeks as profit margins for refiners and gasoline retailers increased, according to the nationwide Lundberg Survey.

The national average for a gallon of regular gasoline rose to $3.9297 on March 23, the survey of about 2,500 gasoline retailers in the continental United States found.

That was a smaller increase than the 12.31-cent rise in the previous survey, which covered the two weeks that ended March 9.

"Profit margins have been exceptionally narrow for quite some time and they have normalized," survey editor Trilby Lundberg told Reuters. "Crude oil price hikes have found their way through to the pump."

The benchmark West Texas Intermediate crude oil closed on Friday at 106.87, down slightly from the March 9 price of $107.40 a barrel.

Lundberg added it was difficult to predict which way gasoline prices would go, but said it would likely take another crude price increase to see a jump in costs at the pump, because the United States is currently sitting on a large cushion of excess refining capacity.

"If crude prices rise, gas will follow," Lundberg said, adding that assurances from Saudi Arabia in the last week that it would boost output to meet any shortfall in supply, may have calmed nervous investors. "If crude prices do not jump, gas prices will peak soon, if they are not already peaking."

Gas demand may finally be on the increase in the United States due to daylight savings time, which began on March 11, she added. With the extension of daylight hours removing the impediment of darkness for drivers, demand is somewhat more robust Lundberg said.

Among cities covered by the survey, the lowest average price was in Tulsa, Oklahoma, at $3.58 per gallon. Drivers in Chicago paid the most at $4.56 a gallon.

(Reporting By Katya Wachtel; Editing by Maureen Bavdek)

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