The average price of a gallon of self-serve regular  gasoline in the Inland Empire decreased a half-cent today to $3.564, its lowest  amount since Dec. 28.
      The average price in Riverside and San Bernardino counties has decreased  for 17 consecutive days and 68 of the past 73, dropping $1.124 over that  span, including 1.2 cents on both Tuesday and Wednesday, according to figures  from the AAA and Oil Price Information Service.
      The average price is 6.6 cents less than one week ago and 23 cents lower  than one month ago, but 4.5 cents more than one year ago.
      Gasoline prices traditionally drop to their lowest amounts of the year  from November through January because of decreased demand, according to Marie  Montgomery Nordhues of the Automobile Club of Southern California.