The average cost of a gallon of gasoline in Tennessee declined by three cents last week, and auto club AAA says that decline should continue into summer.

The average cost of a gallon of gas in Tennessee Sunday was $3.47, down from $3.50 last week.

And although the current average remains substantially higher than the cost of a gallon of gas the same time last year — $3.26 — AAA spokesman Mark Jenkins says that prices have hit their spring peak and should continue falling.

"Motorists are finally getting that steady break in gas prices that we were anticipating," Jenkins said. "The discount at the pump is expected to continue, as prices are forecast to be in line with last year's levels by Memorial Day weekend."

Record supplies are driving gas prices down. The federal Energy Information Administration (EIA) estimates total U.S. crude oil production in April reached its highest monthly average since 1988.

Currently, the national average for gasoline is $3.65 per gallon. The EIA estimates the average for the month to be $3.72, and forecasts that monthly average to fall 21 cents by September.

"Last year, gas prices fell through June, then rose in July," Jenkins said. "This year, record U.S. crude inventories should put downward pressure on gas prices all summer."

The AAA cautioned that natural disasters or supply disruptions could change those forecasts.