Gasoline prices continued their downward drift on Dec. 20, falling around two cents per gallon over the week and down 10 cents from a month ago, with an easing in crude prices helping put downward pressure on costs at the pump. The national average regular gasoline price fell to $3.308 per gallon by Dec. 20, according to the American Automobile Association, down from $3.330 a week ago and $3.410 a month ago. Monday’s national average gas price ranged from a low of $2.896 in Oklahoma to $4.667 per gallon in California. In November, U.S. regular gasoline retail prices averaged $3.39 per gallon, which was the highest monthly average since September 2014, according to the Energy Information Administration. The agency expects prices at the pump to drop to an average of $2.88 per gallon in 2022. Tom Kloza, global head of energy analysis at the Oil Price Information Service at IHS Markit …