ATLANTA (CNN) - Retail gasoline prices fell nearly 1.5 cents during the past two weeks, to $2.93 a gallon of self-serve regular, a national survey said Sunday.

"Both gasoline supply and the use rate of U.S. refining capacity are looking good - they're both normal," said Trilby Lundberg, publisher of the "Lundberg Survey," which tallies prices every two to three weeks at about 5,000 gas stations across the country.

Gasoline prices dipped over the last two weeks and further declines are expected.

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The survey's latest tally, carried out May 19, showed prices had dropped 1.45 cents from May 5, she said.

"The price picture is aided too by slightly lower crude prices during the two-week period," she said, noting that the price of a barrel of West Texas Intermediate on the futures market closed Friday at $68.53, down $1.66.

Two other elements helped explain the price slippage: flat demand for gasoline and heavy imports, she said.

"Unless there are big snafus in refinery operations or a resurgence in oil prices, then ... the price will probably drop further from here," she said.

Wichita drivers paid the least, at $2.59 per gallon of self-serve regular, and San Diego drivers the most, at $3.40, she said.

Here are the average prices for a gallon of regular gas in other U.S. cities:

-- St. Louis: $2.71

-- Minneapolis: $2.72

-- Denver: $2.75

-- Atlanta: $2.81

-- Houston: $2.93

-- Boston: $3.01

-- Long Island: $3.21

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