The average U.S. price of regular-grade gasoline has spiked 10 cents per gallon (3.8 liters) over the past two weeks to $2.73. Industry analyst Trilby Lundberg of the Lundberg Survey says Sunday that jump results mostly from a drone attack this month on Saudi Arabia’s key oil processing facility. The attack briefly slashed the nation’s crude production in half before being restored. The price at the pump is 18 cents lower than it was a year ago. The highest average price in the nation is $3.94 a gallon in San Francisco. The lowest average is $2.24 in Baton Rouge, Louisiana. The lowest reported price reported in Martinsville is $2.22 at the Valero on A.L. Philpott Highway.