Gas prices in the United States increased by more than a dime over the past three weeks, the first increase seen since mid-October, according to a survey published Sunday.

The average price of a gallon of regular gasoline was $3.35 as of Friday, the Lundberg Survey found. That’s an increase of 12 cents from the last survey of 2011, conducted December 16.

“The price hike comes from higher crude oil prices, which pulled up wholesale gasoline prices, but retailers have yet to pass through to motorists all the hikes they received,” publisher Trilby Lundberg said.

If crude oil prices stay steady, it’s likely drivers will see an increase of a few more cents while retailers catch up, she said. “If crude oil declined substantially, then we would not see that increase. It would be hidden within an overall decline.”

It’s impossible to say how much the wholesale price increase was affected by a higher tax on ethanol, she said. On January 1, an ethanol price subsidy in effect for 33 years expired.

The Lundberg Survey tallies prices at thousands of gas stations nationwide.

The city with the lowest average price in the latest survey was Salt Lake City, at $2.86. The highest average was in Los Angeles, with $3.69.

(Source: CNN)