The price for a gallon of regular unleaded gasoline in the United States is edging lower as wholesale prices decline and refinery issues ebb, surveys find.

Motor club AAA reports a national average retail price for a gallon of regular unleaded gasoline at $2.79, about a penny less than last week. An increase in demand, which in part was driven by lower prices at the pump, along with refinery issues led to a steady rise in gasoline prices nationwide.

Tuesday's price is about 5 cents higher than one month ago. Around half of all retail fueling stations in the country were selling gasoline at or below the $2 per gallon mark earlier this year.

"Pump prices in recent days have stabilized or even dropped in many areas as refineries solve productions issues," AAA said in a weekly review of market trends. "Gasoline production typically increases this time of year in anticipation of summer demand, and high profit margins should incentivize refineries to produce more gasoline in the near future, which may help lower gas prices."

South Carolina's state average of $2.48 was the lowest among Lower 48 states. California's was the highest at $3.48 per gallon, followed by Nevada with $3.21.

Patrick DeHaan, a senior analyst with price-watching group GasBuddy, attributed the decline in gasoline prices to a drop in wholesale prices.

"A slightly surprising build in gasoline inventories per the weekly Energy Information Administration seemed to start a selloff in markets that's still unfolding, leading to relief at the pump for many," he said in a statement.

EIA said in a market report for June it expected retail prices to average $2.44 for full-year 2015 and $2.55 for next year.