The national average price of a gallon of unleaded gasoline fell to around the $2.20 level after the Labor Day weekend, which marks the end of the summer driving season, according to data from AAA and the federal government.

The average price fell 2 cents to $2.20 on Sept. 6, according to AAA. The price fell 1.4 cents to $2.223, according to the U.S. Energy Information Administration. The decline came after several weeks of modest increases.

Among the country's regions, the Midwest saw the sharpest decline of 4.7 cents to $2.18 for the week. Many of the remaining regions were essentially flat, according to the federal data.

Some uncertainty over the impact of Hurricane Hermine's impact on Gulf Coast refineries caused modest price increases that reversed when it because clear the storm wouldn't impact production, according to AAA.

Gas prices in four states are below $2 per gallon, including South Carolina ($1.94), Alabama ($1.97), Mississippi ($1.98) and New Jersey ($1.99), according to AAA.

The biggest weekly price decreases are reflected in Michigan (11 cents), Missouri (7 cents), Oklahoma (7 cents), Illinois (6 cents), Minnesota (4 cents), Ohio (4 cents), Alaska (3 cents), Iowa (3 cents), Kentucky (3 cents) and South Dakota (3 cents).

Meanwhile, the average price of diesel fell two-tenths of a cent to $2.407. Diesel is 12.7 cents lower than it was a year ago, according to federal data.