Retail gas prices across the country jumped an average of nearly a quarter per gallon in the past two weeks, according to a survey released Sunday.

Self-serve regular averaged $2.91 a gallon, up from $2.67 two weeks ago, said Trilby Lundberg, who publishes the nationwide Lundberg Survey of 7,000 gas stations.

Also Sunday, OPEC President Edmund Maduabebe Daukoru predicted that oil prices would fall from their current high of just over $75 a barrel to stabilize in the "upper fifties to lower sixties."

Crude-oil prices hit a new record Friday, fueled by concerns about Iran's nuclear ambitions and tight U.S. gasoline supplies.

The Organization of Petroleum Exporting Countries president said the solution to high prices lies in a calmer international environment and boosting refining capacity — not increasing output which would only clog the market.

"If we do the right things by lowering international tensions, oil prices will definitely stabilize," said OPEC President Edmund Maduabebe Daukoru said in Doha, Qatar.

In the Lundberg Survey, mid-grade hit $3 a gallon, up from $2.76, while premium climbed to an average of $3.10, from $2.86 two weeks ago.

The survey covered the period from April 7 through April 21.

Among the stations surveyed, the lowest average price in the country for regular unleaded was in Boise, Idaho, at $2.54 a gallon.

Drivers in San Diego were paying the most for gas, at an average of $3.12 a gallon for regular.