PORTLAND — The average retail gasoline price in Maine continues its downward slide, but still remains higher than it was a year ago.

A survey by the price-watching website MaineGasPrices.com says prices Sunday were 2.6 cents per gallon less than they were a week earlier, averaging $3.37 per gallon.

The statewide average was 12.7 cents per gallon lower than a month ago, but still 27.3 cents per gallon higher than the same day one year ago.

Petroleum Analyst Patrick DeHaan says that as 2012 closes in, retail prices might climb slightly higher again. Upbeat holiday spending, which is indicative of a healthier economy, can lead to higher gasoline prices as they did last year.

The average U.S. price of a gallon of regular gasoline was $3.29 on Sunday, according to the Lundberg Survey of fuel prices. Diesel was down a nickel, to $3.96 a gallon.

Of the cities surveyed, Albuquerque, N.M., had the nation’s lowest average price for gas at $2.84. San Francisco had the highest at $3.67.