The national average price for a gallon of regular unleaded has increased for 20 of the 21 days leading up to Dec. 19 to reach $2.24, which marks the highest level since October, according to AAA.

The price level is three cents higher than a week ago, nine cents higher than a month ago, and 24 cents higher than the same time in 2015. Prices have been increasing ahead of a planned cut in production in January by the Organization of Petroleum Exporting Countries (OPEC).

The Lower Atlantic and Gulf Coast saw the sharpest increases for the week with 4.5-cent increases to $2.226 and $2.053 respectively, according to the U.S. Energy Information Administration. The West Coast is the only region with slightly less expensive gasoline than a year ago.

The nation’s top five most expensive markets are Hawaii ($2.95), California ($2.67), Alaska ($2.62), Washington ($2.59) and the District of Columbia ($2.54), while the five least expensive markets are Arkansas ($2.02), Oklahoma ($2.02), South Carolina ($2.03), Missouri ($2.04) and Texas ($2.05).

Meanwhile, the average price of diesel increased 3.4 cents to $2.527. Diesel is now 24.3 cents higher than a year ago, according to EIA data.