CAMARILLO, Calif. — The average U.S. price of regular-grade gasoline jumped 8 cents over the past two weeks, to $3.10 per gallon.

Industry analyst Trilby Lundberg of the Lundberg Survey said Sunday that the increase is attributed to supply disruption from the 10-day shutdown of the Colonial Pipeline following a cyberattack, and a rise in prices for corn, a key ingredient in corn-based ethanol that must be blended by refiners into gasoline.

The price at the pump is $1.05 higher than it was a year ago.

"Due to the huge drop in demand last year for oil and the massive drop in price, oil producers greatly scaled back but didn’t plan on demand bouncing back so much this year, so supply has not matched the rise in demand, a factor that could raise summer prices higher this year than recent years, until oil producers start ramping back up," said GasBuddy Head of Petroleum Analysis, Patrick De Haan.

When the national average reached $3/gallon on May 12, it was the first time hitting that mark since 2014.

The highest average price in the nation right now is $4.23 a gallon in the San Francisco Bay Area.

The metro area with the lowest average is $2.53 in Houston.