The average price of a gallon of gasoline in the United States rose 1.87 cents over the past two weeks as refiners and retailers absorbed most of the crude oil price increases that have resulted from the crisis in Iraq, according to the Lundberg survey released on Sunday.

Gasoline prices rose to $3.7098 per gallon for regular grade gasoline, according to the most recent survey, which was conducted on June 20.

Crude oil has risen amid questions over access to Iraq's oil supply as an Islamist insurgency mounts there. Refiners and retailers did not pass through the $5 to $6 per barrel increase in crude oil prices during that two-week period.

"That means that their margins on gasoline have shrunk and they are going to need to try to get some of that back soon," said Trilby Lundberg, publisher of the survey.

The price is a premium over this time last year, when costs were $3.5969 per gallon of regular grade gasoline. That increase is due to higher demand overall, not just the higher seasonal increase in prices that occurs each summer, Lundberg said.

Chicago had the highest price within the survey area at $4.15 per gallon for regular while the lowest price was in Tucson where regular grade cost $3.37 per gallon.