The price, for regular grade as of December 18, was the lowest since $2.05 in April 2009 as oil prices continued to slide, survey publisher Trilby Lundberg said.
US crude prices have dropped 17 percent in December.
Gas prices have averaged $2.48 this year, down from $3.37 last year, according to the survey of about 2,500 U.S. filling stations.
Of the cities polled, Tulsa had the lowest average retail price at $1.72, and Los Angeles had the highest at $2.71.
