The average U.S. price for a gallon of regular gasoline dropped significantly in the past week, as the average nationwide for a gallon of regular is at $3.36, down from $3.42 a week ago.  A year ago it was $3.53 per gallon, which was down 2 cents from the previous week.  In Illinois the average for a gallon of regular gas is also down significantly to $3.53 from $3.61 from a week ago, after it had been going up in recent weeks.