A national survey finds the average U.S. price of regular-grade gasoline has plummeted 9 cents a gallon over the past two weeks to $3.58.
That's the largest drop this year.
Industry analyst Trilby Lundberg said Sunday the decrease came despite a rise in crude-oil prices.
Lundberg says U.S. refiners, enjoying plentiful supplies, aggressively cut wholesale prices to chase sales.
Midgrade averages were $3.78, and premium averages were $3.93.
The U.S. average retail diesel price is down 4 cents per gallon, to $3.90.
The lowest average price Lundberg found in the lower 48 states was $3.23 in Tulsa, Oklahoma. The highest was $4.03 in San Francisco.
The lowest average price in California was $3.86 in Sacramento.