The national average price of gasoline continued its steady climb, rising 3.5 cents to $3.547 per gallon for the week ending March 17, according to federal data.

The increase was the seventh consecutive in as many weeks. The average price is 14.9 cents lower than it was a year ago, reports the U.S. Energy Information Administration.

Gasoline rose in all but one of the regions tracked and saw the sharpest increase come in the Lower Atlantic, where it rose 5.7 cents. The price fell in the Central Atlantic region by a fourth of a cent. Gasoline now costs at least $3.50 in 30 states, according to the AAA's Daily Fuel Gauge Report. A week ago, 25 states met that bar.

Meanwhile, the national average price of diesel fuel fell 1.8 cents to $4.003 per gallon. Diesel costs 4.4 cents less than it did a year ago.