Gasoline prices averaged $3.7074 per gallon on March 22, down from $3.7394 per gallon on March 8, which was the first decline of the year, according to Trilby Lundberg, editor of the Lundberg Survey.
Over the past four weeks, prices have fallen 8.76 cents. In the nine weeks through Feb. 22, retail gasoline prices rose more than 53 cents.
The recent decline reflects lower Brent crude oil prices as well as the completion of various maintenance and repair projects by refiners.
"Some of the big projects were taking place in California and,... in these two weeks, the average retail price in California dropped 12 cents," Lundberg said, noting that California's average price, at $4.03, is still above the national average.
According to Lundberg's survey, which canvases about 2,500 gas stations, the U.S. city with the most expensive gasoline was Chicago, where a gallon cost $4.10. Billings, Montana, had the least expensive gasoline, at $3.33 a gallon.
Brent May crude lost $2.16 a barrel last week, with financial problems in Cyprus reviving worries about the outlook for petroleum demand in Europe.
Lundberg said the current average gasoline price in the survey is 22.23 cents lower than the year-ago price.