77.5% is the change from 40 to 71
Calculation steps:
[( 71 - 40 ) ÷ 40] x 100 = 77.5%
Formula
Percentage change = [(71 - 40) / 40] x 100
Subtract the new number by the original number
71 - 40 = 31
31 ÷ 40 = 0.775
0.775 x 100 = 77.5%
Example