a gallon of gas was 1.03 two years ago now it is 1.59 what is the rate of increase?
1.59 / 1.03 =1.544 -1 x 100=54.4% increase in 2 years.
Sqrt(1.544)=1.243 - 1 x 100=24.3% average annual increase in a gallon of gas.
+20 
