The average price of gasoline dropped more than 7 cents over the past three weeks, to $3.11 per gallon of self-serve regular, the first price drop since January, a national survey said Sunday.

The "Lundberg Survey" of about 5,000 gas stations was carried out June 8 and May 18.

"It's unlikely we can see the other 93 cents any time soon," she told CNN in a telephone interview.

Most of that 7 cents relief came from lower prices charged for gas produced in refineries outside the United States, she said.