The national average price of regular unleaded moved 1 cent lower to $2.57 for the week ending Dec. 9, as Ohio, California, and several other states saw more significant price declines.

The price level is now 5 cents lower than a month ago and 15 cents higher than a year ago, according to AAA.

"Since the end of October, gasoline demand has mostly decreased as gasoline stocks have mostly increased, paving the way for cheaper gas prices," said Jeanette Casselano, AAA spokesperson. "AAA expects stocks to continue to grow and drive gas prices even cheaper through year-end."

States with the biggest price declines include Ohio (12 cents), California (10 cents), Nevada (7 cents), Oregon (6 cents), Utah (5 cents), Idaho (4 cents), and Washington (4 cents). States with the largest price increases include Michigan (10 cents), Florida (8 cents), and Indiana (7 cents).

States with the least expensive markets now include Texas ($2.20), Mississippi ($2.22), Oklahoma ($2.23), Missouri ($2.23), Louisiana ($2.25), Alabama ($2.27), South Carolina ($2.27), Arkansas ($2.27), Kansas ($2.28), and Virginia ($2.30).

Meanwhile, the average price for diesel fuel fell 2.1 cents to $3.049, which is 11.2 cents lower than a year ago, according to the U.S. Energy Information Administration.