BOSTON (AP) - The price of a gallon of gas in Massachusetts has plummeted 9 cents in the past week.

AAA Southern New England reports Monday that self-serve, regular is now down to an average of $3.47 per gallon, a nickel below the national average.

The price in Massachusetts is 18 cents lower than a month ago and 42 cents lower than at the same time last year.

AAA found a gallon of self-serve, regular selling as low as $3.29 per gallon and as high as $3.73.