Prices at the pump in Maine have fallen by a little more than a penny in the past week, but a gallon of gas remains a dime above the national average. Price-monitoring website MaineGasPrices.com reports Monday that the average retail cost of a gallon of gas in Maine is now $3.67, compared to the national average of $3.57. Maine prices are now more than 17 cents per gallon lower than the same day a year ago and nearly 11 cents per gallon lower than a month ago. A company analyst says prices may inch up slightly due to a decline in gasoline inventories. The Maine price is based on a survey of more than 1,200 gas stations.