Average price of gas up by a penny per gallon to $3.25; Bay Area average $4.47

The average U.S. price of regular-grade gasoline went up by a penny over the past two weeks, to $3.25 per gallon.

That's $1 more than a year ago.

Industry analyst Trilby Lundberg of the Lundberg Survey said Sunday the small rise was due to an increase in the cost of crude oil.

Nationwide, the highest average price for regular-grade gas is in the San Francisco Bay Area, at $4.47 per gallon. The lowest average is in Houston, at $2.72 per gallon.

According to the survey, the average price of diesel was $3.35 a gallon, up a fraction of a cent.