The national average price of a gallon of unleaded gasoline remained essentially flat at $2.28 over the Presidents' Day weekend, according to AAA.

The price has fallen five cents in the past month and remains 56 cents more than a year ago.

Federal data showed a five-tenths cent increase to $2.302, which is 57.2 cents higher than a year ago.

Prices remained flat due to lower driving demand and an oversupplied market after an increase in U.S. production. As refinery maintenance season begins and driving demand increases, some of the U.S. gasoline supply could be soaked up, according to AAA.

The nation’s top five markets that have seen the largest monthly decreases include West Virginia $2.27 (11 cents), New Jersey $2.33 (9 cents), Pennsylvania $2.53 (9 cents), Illinois $2.29 (9 cents) and Delaware $2.22 (9 cents).

The nation’s top five most expensive markets include Hawaii ($3.12), California ($2.90), Washington ($2.74), Alaska ($2.71), and Oregon ($2.54).

Meanwhile, the average price of a gallon of diesel increased seven-tenths of a cent to $2.572, which is 58.9 cents higher than a year ago.