The average price of a gallon of self-serve regular gasoline in the Inland Empire continued increasing Sunday, but barely, rising one-tenth of a cent for the second consecutive day.

   The average price in Riverside and San Bernardino counties has risen 27 of the past 28 days to $3.99, its highest amount since Sept. 20, according to figures from the AAA and Oil Price Information Service.

   The average price has risen 23.8 cents over the past 28 days and is 5 cents more than one week ago and 23.8 cents higher than one month ago, but 15.8 cents less than one year ago.