PORTLAND – AAA says the average price paid for regular gasoline dipped by another penny after falling below $4 a gallon over the weekend.

AAA said gas prices dropped about a penny over the weekend from $4.017 to $3.997, and then fell again to $3.981 on Monday. On average, that’s a drop of 12 cents from a month ago but prices varied by market. Portland was slightly above $4, while Bangor was $3.92.

Maine’s drop mirrors a national trend. The Lundberg Survey of 7,000 gas stations nationwide indicates prices are at their lowest level since May 16.

Nationally, the average price of regular gasoline at self-serve stations dipped to $3.996 a gallon Friday. Still, the survey showed the average U.S. price for gas is $1.11 higher than it was a year ago.