South Carolina had the cheapest gas in the country for the second year in a row in 2013, and prices are expected to stay low again this year, AAA said in a report released Thursday.

Gas in South Carolina was about $3.24 per gallon last year, the palmetto state's lowest fuel price since 2010.

The decline mirrors a nationwide trend of falling gas prices. Americans paid an average of $3.49 per gallon last year, about 11 cents less than 2012.

The Charleston metro area had the most expensive gas in the state last year with an average gas price of $3.29. Greenville and Spartanburg paid the lowest amount for gas, about $3.19 per gallon.

The AAA report said the cheaper gas is likely related to an increase of fuel-effecient cars on the road and more reliance on North American crude oil. Also, oil refineries have increased their capacities, which means gas production can more quickly respond to consumer demand.

"We expect these trends to continue into 2014," said David E. Parsons, president and CEO of AAA Carolinas.

On Wednesday, gas in South Carolina was about $3.12 per gallon, three cents cheaper than New Year's Day last year. The AAA report said prices will stay low throughout the month as demand falls, but that prices are typically driven up in February, when oil refineries conduct seasonal maintenance.

While it's certainly a relief for South Carolinians at the pump, cheaper gas is also encouraging more travelers to visit the state.

About 80 percent of tourists in South Carolina travel by car, according to the South Carolina Department of Parks, Recreation and Tourism.

The falling gas prices in recent years has bolstered the state's tourism industry, said Duane Parrish, director of the state PRT.

"If you think about our geographic size, (South Carolina has) a lot to offer," he said. "You can change from mountains to the beach by driving three and a half hours. In other states you can't access the mountains and the coast in the same day."

Reach Abigail Darlington at 937-5906 and follow her on Twitter @A_Big_Gail