The national average price of a gallon of gasoline has reached $2.33 per gallon — a level last seen in January, reports AAA.

The gasoline price average increased 4 cents from a week ago, 1 cent from a month ago, and 27 cents from a year ago. National prices have increased on six of the past seven days. Price increases should continue during the season of refinery maintenance and the arrival of the more expensive summer-blend gasoline, according to AAA.

The 10 least expensive state markets now include South Carolina ($2.04), Tennessee ($2.08), Mississippi ($2.08), Alabama ($2.09), Oklahoma ($2.10), Arkansas ($2.10), Missouri ($2.11), Louisiana ($2.12), Virginia ($2.13), and Texas ($2.15).

The 10 state markets with the largest weekly increases include Ohio (18 cents), Michigan (16 cents), Indiana (14 cents), Illinois (11 cents), Wisconsin (7 cents), Delaware (7 cents), West Virginia (6 cents), Kentucky (5 cents), Oregon (5 cents) and Georgia (5 cents).

Meanwhile, the average price of diesel increased 2.4 cents to $2.556. Diesel is now 44.1 cents higher than a year ago.