(Calculating inflation and project cash flows) On July 25,2011 , the average price of a gallon of gasoline was $3.60. Just 8 years later the price of that same gallon of gas was $2.02. What was the rate of inflation (deflation) in the price of a gallon of gas over the period? The annual rate of inflation (deflation) in the price of a gallon of gasoline over the 8 years was \%. (Round to two decimal places.)