The average price of a gallon of self-serve regular gasoline in Riverside County increased one-tenth of a cent Monday to $4.311, a day after rising 1.1 cents. It is 3.5 cents more than one week ago and eight-tenths of a cent more than one month ago, but 27.5 cents less than one year ago, according to figures from the AAA and Oil Price Information Service. The average price has dropped $2.062 since rising to a record $6.373 on Oct. 5, 2022.