HEATHROW, Fla. — The national average price of a gallon of regular unleaded leveled off at $2.81 for the week ending May 7, according to AAA, following steady increases that put the price at more than 12% since early March.

Gasoline is now 45 cents more expensive than it was a year ago. With the summer driving season on the horizon, prices are expected to move higher at a steadier rate, AAA officials said.

“If this past week’s moderate increases are any indicator of what’s to come, the fast rate at which gas prices were increasing may be slowing down,” said AAA spokesperson Jeanette Casselano. “On the week, the national average held steady and 19 state averages remained flat or saw decreases in gas prices. Despite this stability, drivers on the West Coast and in Idaho, Utah, and Pennsylvania are paying $3 per gallon.”

States with the most expensive gasoline include California ($3.63), Hawaii ($3.63), Washington ($3.32), Alaska ($3.28), Nevada ($3.25), and Oregon ($3.23).

States with the largest yearly increases include Indiana (up 66 cents), California (up 66 cents), Utah (up 63 cents), Arizona (up 60 cents), Hawaii (up 56 cents), Idaho (up 55 cents), and Nevada (up 55 cents).

Meanwhile, the average price of diesel increased 1.4 cents to $3.171 per gallon, which is 60.6 cents higher than a year ago.