Gas below $2.50 and sinking
Unleaded regular gas falls for 48th straight day, prices down more than a third from summer's record high.
NEW YORK (CNNMoney.com) -- Gasoline prices sank to their lowest levels in more than 20 months, according to a nationwide survey of credit card swipes at gasoline stations.
The average price of unleaded regular gas dropped 2.4 cents to $2.391 a gallon, according to a survey released Tuesday by motorist group AAA. The last time gas was this low was Feb. 28, 2007.
Gas has fallen 48 straight days, since just after Hurricanes Gustav and Ike battered the Gulf coast in September.
Prices are now down 41.88%, or $1.723, from the record high price of $4.114 a gallon set July 17. The average price dropped below $3 a gallon on Oct. 18 for the first time in nearly nine months.
Prices have tumbled 20.4% or 61.3 cents from the same time last year.
Even with falling prices, demand for gas continues to drop. Americans are driving 5.6% fewer miles than last year, according to a recent U.S. Department of Energy report.
Alaska reported the highest current-state-average gas price, at $3.466 per gallon, with Oklahoma posting the lowest current-state-average price, $2.061 per gallon.
Retail gas prices have benefited from lower oil prices. The price of crude has dropped by more than half since it peaked near $150 a barrel in mid July.
The AAA figures are state-wide averages, and many drivers have reported even lower prices across the country. 
