The national gasoline price increased 6 cents to $2.33 for the week ending Feb. 19, as 28 states saw their average price rise at least 5 cents, according to AAA.

Ths price increase, which was the largest of the year, moved the current price 9 cents above a month ago and 19 cents below a year ago.

"Motorists are seeing more expensive gas prices as a result of ongoing refinery problems coupled with crude oil prices hitting their highest level so far this year as global crude inventories tighten," said Jeanette Casselano, AAA spokesperson. "Inventories are likely to continue to tighten and keep gas prices higher through the end of the month."

Demand, as measured by crude oil output, fell for a second week in a row to 8.6 million barrels per day, according to the U.S. Energy Information Administration. Severe, cold weather in the plains and northeast has pushed demand lower. For the week ending Feb. 8, inventories increased 408,000 barrels to 258.3 million.

States with the least expensive gasoline include Alabama ($2.04), Mississippi ($2.04), Missouri ($2.07), Arkansas ($2.07), Louisiana ($2.07), South Carolina ($2.08), Texas ($2.09), Colorado ($2.09), Kansas ($2.11), and Virginia ($2.11).

States with the largest weekly increases include Michigan (up 16 cents), Oklahoma (up 12 cents), Minnesota (up 11 cents), Texas (up 11 cents), Kansas (up 10 cents), Arkansas (up 10 cents), Delaware (up 10 cents), Maryland (up 9 cents), Iowa (up 9 cents), and Kentucky (up 9 cents).