Camarillo, Calif. ? A national survey shows gas prices have dropped a fraction below the $4-dollar mark.

The average price of regular gasoline at self-serve stations was $3.996 a gallon Friday, according to the Lundberg Survey of 7,000 gas stations nationwide, released Sunday.

Prices are at their lowest level since May 16 and are an average of 11.7 cents less per gallon than two weeks ago. Still, the average U.S. price for gas is $1.11 higher than it was a year ago.