The national average price of gasoline has been inching lower to $2.24 per gallon over the past nine days and drivers are now paying 3 cents less than a year ago as of Oct. 17, according to AAA.

Prices continue to fluctuate in areas of the country that have been affected by Hurricane Matthew, and several refinieres across the country have gone offline to address planned and unplanned maintenance.

Volatility has increased in the Midwest as Indiana, Ohio, Michigan, and Illinois saw the highest declines. The average price in those states fell 14 cents, 12 cents, 10 cents, and 8 cents respectively.

The West Coast remains the most expensive market for gasoline and includes the only six states with average prices above $2.50, including Hawaii ($2.87), California ($2.78), Washington ($2.71), Alaska ($2.63), Oregon ($2.52), and Nevada ($2.51).

Federal data nearly mirrored AAA's findings, as the U.S. Energy Information Administration reported a 1.5-cent increase to $2.257 for the week ending Oct. 17. The price is 2 cents higher than a year ago, by their data.

Among the regions tracked by EIA, prices in New England and the Midwest fell, while the other nine regions saw prices rise slightly higher. The Midwest price saw the steepest decline of 6.6 cents to $2.155.

Meanwhile, the average price of diesel increased 3.6 cents to $2.481. The price is 5 cents higher than a year ago.