NEW YORK (CNN) - Gas prices surged 20 cents over the past three weeks to an all-time high of $2.50 per gallon of self-serve regular, a national survey said Sunday.

The price surge "does smash the all-time record high for the third time this year," Trilby Lundberg, publisher of the Lundberg Survey, said.

"Crude oil has caused this jump at the pump," she said of the survey, taken Aug. 12 at about 7,000 gas stations in every state. "And even at the current record-breaking pump prices, gasoline demand, while not galloping, is still growing."

However, should the crude oil supply remain undisrupted, then, "The gasoline price surge itself will probably be ending soon, if it has not already," Lundberg said, citing an expected decrease in gasoline demand after August.

"Our demand for for gasoline is always highest for June, July and August," she said of the summer months, when families typically take vacations.

Lundberg said the lowest average price in the Aug. 12 survey was in Cheyenne, Wyo., where a gallon of self-serve regular cost $2.31. The highest was in San Diego, Calif., where a gallon cost $2.76.

Though a record in absolute terms, the price is still well shy of a record, if adjusted for inflation. The peak price would have been set during the Iranian revolution in March 1981, when a gallon of gas cost about $3 in today's dollars, Lundberg said.

Here are some prices in other cities:

• Salt Lake City - $2.33
• Charleston, S.C. - $2.35
• Houston - $2.39
• Atlanta - $2.49
• Boston - $2.50
• St. Louis, Mo. - $2.55
• Chicago $2.64