The average price of a gallon of unleaded gasoline increased 1.8 cents to $2.399 for the week ending June 13, according to federal data.

The nation's gasoline average price is now 43.6 cents lower than it was a year ago, as it increased in six regions and declined in three regions tracked by the U.S. Energy Information Administration. The average price increased 5.7 cents to $2.466 in the Midwest and fell 2.3 cents on the West Coast. Prices were essentially flat in five of the nine regions.

The national average was slightly lower ($2.378), according to the AAA, which reported that prices have reached a 2016 high and the most expensive average since September. Pump prices have increased for 28 of the past 33 days. California now has the highest average price among states.

Meanwhile, the average price of diesel increased 2.4 cents to $2.431. Diesel is now 43.9 cents lower than it was a year ago.