The national average fell 1.9 cents to $2.068 per gallon of regular gasoline, according to the daily survey conducted for the American Automobile Association, a motorist group.
The decline brings the price of gas down nearly 50% from the record high of $4.114 reached in mid-July. Prices were down almost $1.03 per gallon from a year ago and 88.6 cents since one month ago.
Gas prices have fallen below an average of $2 a gallon in 18 states. It was cheapest in Missouri, at an average of $1.773, according to AAA.
The price in nearly all remaining states stands below $3 a gallon. Only Alaska remains above that mark, at $3.150 per gallon; Hawaii, which had been above $3, fell to $2.997 a gallon.
The price of crude oil, the main component of petrol fuels, has also declined as investors fear the global economic slowdown will reduce demand for fuel.
On Monday, oil futures settled to $54.95 per barrel, their lowest levels since Jan. 29, 2007. Prices have not dipped below $50 since May 24, 2005.
The AAA figures, compiled by Oil Price Information Services, are state-wide averages based on credit card swipes at up to 100,000 service stations across the nation. These are state-wide averages, and individual drivers may see different fuel prices in their area.
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