Sept 22 (Reuters) - The average price for a gallon of gasoline in the United States fell 6.4 cents in the last two weeks, as crude oil declined and refiners passed on the difference, according to the Lundberg survey released on Sunday.
The average price was about 31 cents lower than a year ago, based on the Sept. 20 survey of some 2,500 retail stations in the 48 contiguous states.
Trilby Lundberg, survey editor, said the rise came alongside a decline in the price of crude oil. Crude has fallen as Libya has produced more and there have been signs of diplomatic progress regarding Syria and Iran.
"California did buck the trend because of some recent hiccups in the California refining capacity affecting the West," Lundberg said. "Prices rose at the pump about 16 cents in California, but the spike has already died as those glitches have already been resolved."
Charleston, South Caroline, had the cheapest gasoline in the survey at $3.14 per gallon, while drivers in San Francisco, paid the most at $4.01 per gallon. (Reporting by Caroline Humer; Editing by Maureen Bavdek)