CAMARILLO, Calif. (AP) — A survey says the average price of a gallon of regular gasoline in the U.S. has fallen 4 cents over the last three weeks to $3.67.

Industry analyst Trilby Lundberg said Sunday that crude oil prices fell over news that Libyan output has risen and Iraq’s production was not substantially harmed by recent violence.

The survey taken Friday shows the average price for a gallon of midgrade gas was $3.86 and the average price for a gallon of premium was $4.01. Diesel averaged $3.94 a gallon.

Of cities surveyed in the continental U.S., Tulsa, Oklahoma, had the lowest average price at $3.35 a gallon. San Francisco had the highest average at $4.12 a gallon.

In California, the average price for regular gasoline was $4.07 a gallon.

In Nebraska, the average price for a gallon of Regular is $3.47