The national average price for a gallon of regular unleaded fell 2 cents to $2.22 for the week ending May 9, according to federal data.

The price of the fuel is now 47.1 cents lower than it was a year ago. For the week, regional fuel price averages were mixed, as five regions saw price increases, while four others saw a price decline. The Rocky Mountain and West Coast without California rose 4.7 cents ($2.214) and 3.9 cents ($2.373) respectively. The Midwest price fell 6.7 cents to $2.116.

State-level prices saw scant changes as California ($2.803) and Hawaii ($2.642) again have the most expensive gasoline. Five state averages remain below $2, including Oklahoma's $1.95 that's the nation's lowest.

Meanwhile, the price of diesel fell five-tenths of a cent to $2.271 per gallon. Diesel is now 60.7 cents lower than it was a year ago.