Photo via Wikimedia.

Photo via Wikimedia.

The national average price of gasoline remained unchanged at $3.704 per gallon for the week ending June 30, according to the U.S. Energy Information Administration.

Gasoline prices have remained essentially flat since early May, but the price of a gallon of regular unleaded is now 20.8 cents higher than it was a year ago.

The price of gasoline rose slightly in seven of the regions tracked by the EIA, and fell in two regions, including the Midwest and Gulf Coast. It fell 2.2 cents in the later region. The sharpest spike came on the West Coast where it rose 2.5 cents.

The average price of gasoline remains at least $3.50 in 42 of the 50 states and the District of Columbia, according to the AAA's Daily Fuel Gauge Report.

Meanwhile, the average price of diesel rose one-tenth of a cent to $3.92 per gallon. The price of diesel is now 10.3 cents higher than it was a year ago.