Gas prices in Maine tumbled by a dime per gallon in the past week, but Hurricane Sandy is creating uncertainty in the market. Price-monitoring website MaineGasPrices.com reports Monday that the average retail cost of a gallon of gas dropped by more than 10 cents to an average of $3.67. That’s still 11 cents above the national average. The current price in Maine is now almost 16 cents per gallon higher than at the same time last year, and more than 27 cents lower than a month ago. A company analyst says Hurricane Sandy may cause disruptions in production and delivery, but disruptions in supply may be offset by area-wide shutdowns of business, leading to curtailed demand.