The percentage change between two numbers, an original number to a new number, calculated by these steps, first subtract the new number by the original number, then divided it by the original number, and finally multiply it by 100.
What is the percentage of change from X to Y
Percentage = [( Y - X ) ÷ X ] x 100
Percent change from 50 to 70
[( 70 - 50 ) ÷ 50] x 100 = 40%