The average price of a gallon of self-serve regular gasoline in the Inland Empire dropped today to its lowest amount of the year, falling six-tenths of a cent to $3.59.

   The average price in Riverside and San Bernardino counties has fallen 57 of the past 58 days and is 4 cents less than one week ago, 19.6 cents lower than one month ago and 23.7 cents below what it was one year ago, according to figures from the AAA and Oil Price Information Service.

   The dropping pump prices are the result of lower wholesale prices and the Nov. 1 switch to winter blend gasoline, which costs less to produce, according to Jeffrey Spring of the Automobile Club of Southern California.