Gasoline at 21-month low
AAA survey shows average pump price just below $2.20 a gallon after 57 days of decline.
NEW YORK�(CNNMoney.com) -- Gasoline prices fell to their lowest level in 21 months Thursday, sinking below the $2.20-a-gallon mark, according to a survey for a motorist group.
The average price of unleaded regular gas dropped 2.4 cents to $2.178 a gallon from $2.202 the day before, according to the survey from motorist group AAA.
The last time gas was this low was Feb. 5, 2007, when the AAA reported the price at $2.177 a gallon.
Gas has fallen 57 straight days in the AAA survey, since just after Hurricanes Gustav and Ike battered the Gulf Coast in September.
Prices have dropped 47.06%, or $1.936, from their record high of $4.114 a gallon set July 17, according to AAA. The average price per gallon dropped below $3 on Oct. 18, the first time in nearly nine months.
Gas was down 93 cents from year-ago levels, a decrease of 29.99%. In the past month, prices have dropped 98 cents, a decrease of 31.14%.
Even as gasoline prices fall, demand has continued to slip. MasterCard's weekly survey of gas station credit card swipes showed demand down 4.2% last week, compared to the same period last year.
By state, Alaska reported the highest average gas price, at $3.280 per gallon, while Missouri boasted the cheapest, at $1.886 a gallon, according to AAA.
Missouri is one of six states with posted prices below $2 per gallon.
Crude prices, which make up roughly half of gasoline prices, have fallen more than 60% since hitting a record $147.27 a barrel on July 11. U.S. crude for December delivery rose Thursday $2.08 to $58.24 a barrel in New York trading.
The AAA figures are state-wide averages based on credit card swipes at up to 100,000 service stations across the nation. 
