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LOS ANGELES — Average California gasoline prices jumped 23 cents in the last week, passing $4 a gallon in Los Angeles, fuel surveys show.

This surge follows a year in which the nation’s motorists spent a greater percentage of their annual income on gasoline than at any time in the last three decades, the Energy Department said.

Gasoline expenditures were higher despite a sharp improvement in automobile fuel economy, according to a separate report.

The average cost for a gallon of regular gasoline in California jumped to $3.914 on Monday, up 23.4 cents from a week earlier, according to the AAA Fuel Gauge Report.

The Energy Department reported a similar increase for California of 22.8 cents a gallon, to $3.904, in its separate price survey.

Refinery maintenance was one reason for the surge, said Denton Cinquegrana, executive editor of the Oil Price Information Service.

“California has a lot more planned refinery maintenance than it usually has at this time of year,” Cinquegrana said. “And most of that is concentrated in Southern California.”

Los Angeles County, for example, averaged $4.017 a gallon Monday, up 24.8 cents over the last week, the AAA report said.

Read more at KTLA