New York (CNN Business) The average price of a gallon of gas has fallen below $2 in the United States — the lowest price in four years, according to AAA.

Not even two weeks ago , the price of a gallon of gas was $2.19, but could be purchased for $2 or less in about a dozen of states. Today, drivers can find a gallon of gas for $1.99 or less at roughly 70% of US gas stations, AAA said.

"This is unprecedented," Tom Kloza, head of energy analysis for the Oil Price Information Service, told CNN Business at the time.

AAA said in a press release Tuesday that it expects gas prices to fall to $1.75 or less in April. Kloza, however, predicts they will continue to drop beyond that, to between $1.25 to $1.50 per gallon in the next few months.

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