PORTLAND (AP) — Gas prices have gone up 4 cents a gallon in the last week in Maine.

Gasoline price-monitoring website GasBuddycom reports Monday that the average cost of a gallon of gas in Maine is up to $2.31, 18.8 cents per gallon higher than in the past month, but still $1.22 lower per gallon than at this time last year.

The price per gallon in Maine is 3 cents above the national average.

The Maine price is based on a survey of more than 1,200 gas stations