The average price of a gallon of unleaded gasoline increased 4.1 cents to $2.834 for the week ending July 13, while regional prices were mixed, according to federal data.

Gasoline has been creeping higher but remains 80.1 cents lower than it was a year ago. Five of the nine regions tracked by the U.S. Department of Energy's Energy Information Administration saw lower prices with increases of between 1.1 and 1.5 cents in the East Coast, New England, Central Atlantic, Lower Atlantic, and Midwest. The sharpest increase came on the West Coast, which saw a 29.2-cent increase to $3.589 per gallon.

Among states, California recaptured the top position from Alaska with the most expensive gasoline at $3.715 per gallon. Six other states have $3-per-gallon gasoline. At the other end of the spectrum, four states have gasoline cheaper than $2.50, including South Carolina at the bottom of the list at $2.411.

Meanwhile, the average price of diesel increased 1.8 cents to $2.814 per gallon. A gallon of diesel is now $1.08 higher that it was a year ago.