(CNN) -- U.S. gasoline prices have decreased by less than a cent in the past two weeks, though some regions saw an increase due to an oil pipeline leak, according to a new nationwide survey.
The latest Lundberg Survey, conducted on September 10, found the average price of self-serve regular at $2.69 per gallon -- down .8 cents since the last survey, conducted two weeks before. Survey publisher Trilby Lundberg said gas prices were expected to stay steady as long as crude prices remain steady.
"If crude stays in its common range, gas prices will change little in the immediate future," Lundberg told CNN. Crude prices have remained between $70 and $80 a barrel throughout the year.
But it was precisely speculation over crude oil prices because of an oil pipeline leak in Illinois that was behind an increase at the wholesale and pump prices in the Midwest and parts of the Gulf Coast, Lundberg said.
Cities including St. Louis, Missouri, Minneapolis, Minnesota, Chicago, Illinois, Tulsa, Oklahoma, and Denver, Colorado, saw upticks at the pump.
The perception of a supply shortage moved the prices, but if the actual event is short-lived and the shortages do not materialize, prices will settle back to relative stability, Lundberg said.
In general, flat demand and supply side strength has kept prices steady, she said.
At $2.69 per gallon, gas prices were 9.88 cents higher than a year ago.
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 $3.06 per gallon; the lowest were in Newark, New Jersey, at $2.45.
Average per-gallon prices in other cities:
Atlanta, Georgia: $2.58
Baton Rouge, Louisiana: $2.49
Boston, Massachusetts: $2.63
Chicago, Illinois: $2.89
Jackson, Mississippi: $2.47
Houston, Texas: $2.46
Miami, Florida: $2.66
Salt Lake City, Utah: $2.87
St. Louis, Missouri: $2.69