(CNN) -- Gasoline prices at the pump have climbed more than 7 cents per gallon in the past two weeks, but could plummet soon with declining crude oil prices, according to a survey published Sunday.
The national average for a gallon of gasoline is $2.92, the Lundberg Survey found in an analysis conducted May 7.
But drivers will likely start paying less for gas in the coming days as oil prices fall, survey publisher Trilby Lundberg told CNN.
"Retail prices will be tumbling down," she said. "But we cannot know how much or exactly when."
Crude prices have dropped about $1.78 per gallon in the past two weeks, she said.
While not guaranteed, the likely trend for dropping oil prices means the national average may not reach the $3 mark all summer, Lundberg said.
Demand for gasoline remains down because of high unemployment and related reductions in driving, she said.
The current average price of gasoline is nearly 62 cents above the price of a gallon of self-serve a year ago, Lundberg said.
The survey tallies prices at thousands of gas stations nationwide.
The city with the lowest average price in the latest survey was Tulsa, Oklahoma, at $2.72. The highest in the most recent survey was Chicago, Illinois, at $3.22.
Among average per-gallon prices in other places:
-- Houston, Texas - $2.75
-- Phoenix, Arizona - $2.86
-- Atlanta, Georgia - $2.89
-- Boston, Massachusetts - $2.93
-- Seattle, Washington - $3.09
-- Long Island, New York - $3.10
-- Los Angeles, California - $3.12