The national average price for gasoline fell 4.3 cents to $2.778 for the week ending Dec. 1, continuing a fuel price decline expected to mirror the declining price of oil.

Brent crude reached $70 a barrel for the week ending Nov. 28 and has declined 40 percent since June. The gasoline price decline began in late June and has reached a four-year low. Gasoline averaged $3.704 per gallon at the time, according to the U.S. Department of Energy.

The average price of gasoline now costs 49.4 cents less than it did a year ago. It fell in nine regions and had its sharpest drop in the Rocky Mountain region of 7.2 cents to $2.861 per gallon. The region with the lowest price remains the Gulf Coast region at $2.531 per gallon.

Gasoline prices have fallen below $3 per gallon in 42 states, and below $2.75 per gallon in 18 states. Missouri has the lowest average price of $2.472 per gallon, according to the AAA's Daily Fuel Gauge Report.

Meanwhile, the average price of diesel fuel fell 2.3 cents to $3.605 per gallon for the week. Diesel now costs 27.8 cents less than it did a year ago.