(CNN) -- U.S. gasoline prices have decreased a little more than 7 cents per gallon in the past two weeks, and lower demand in September is expected to keep prices steady, according to a new nationwide survey.
The latest Lundberg Survey, conducted on August 27, found the average price of self-serve regular at $2.70 per gallon -- down 7.54 cents since the last survey, conducted two weeks before.
Survey publisher Trilby Lundberg said gas prices were catching up to a decrease in crude prices.
"Absent any upset in the price of crude, (gasoline) prices should see little change or even a small drop," Lundberg told CNN.
There is a plentiful supply of gas, and September marks the beginning of a traditional period of lower gas consumption that should keep prices steady, outside of any large fluctuations in crude prices, she said.
At $2.70 per gallon, gas prices were at their lowest since late February.
The latest survey involved about 2,500 stations in the continental United States. The highest prices were found in San Francisco, California, where the average price was $3.13 per gallon; the lowest were in St. Louis, Missouri, at $2.39.
Average per-gallon prices in other cities:
Atlanta, Georgia: $2.57
Boston, Massachusetts: $2.67
Denver, Colorado: $2.66
El Paso, Texas: $2.75
Los Angeles, California: $3.03
Seattle, Washington: $3.03
Tulsa, Oklahoma: $2.54