CAMARILLO, Calif. -- The average national price of gasoline rose nearly 12 cents in the past three weeks, marking the first price hike after six months of steady decreases, according to a national survey released Sunday. The average price of regular gasoline Friday was $1.78 a gallon, oil industry analyst Trilby Lundberg said. The price of mid-grade was $1.91 a gallon and the price of premium was $2.02 a gallon. The increase was the first since July 11, when the average national price peaked at $4.11 a gallon. Of cities surveyed, the nation's lowest price was $1.34 in Billings, Mont. The highest price was $2.32 in Anchorage, Alaska.