127.5% is the change from 40 to 91
Calculation steps:
[( 91 - 40 ) ÷ 40] x 100 = 127.5%
Formula
Percentage change = [(91 - 40) / 40] x 100
Subtract the new number by the original number
91 - 40 = 51
51 ÷ 40 = 1.275
1.275 x 100 = 127.5%
Example