The average price of a gallon of unleaded gasoline has fallen 6.4 cents to $3.056 per gallon for the week ending Oct. 27, according to federal data.

The average price remains at a four-year low. Gasoline now costs 23.8 cents lower than it did a year ago, according to the U.S. Energy Information Administration. The price again fell in all nine regions tracked by the agency. The sharpest decline came on the West Coast where it fell 10 cents to $3.324. The price has fallen below $3 per gallon in the Lower Atlantic ($2.947) and Gulf Coast ($2.83) regions.

The price of gasoline now costs at least $3.50 in only Hawaii ($4.054) and Alaska ($3.768). It has fallen below $3 per gallon in 17 states and has the lowest average price in South Carolina at $2.785, according to the AAA's Daily Fuel Gauge Report.

Meanwhile, the average price of diesel fell 2.1 cents to $3.635 per gallon. Diesel now costs 23.5 cents lower than it did a year ago.