-69% is the change from 100 to 31
Calculation steps:
[( 31 - 100 ) ÷ 100] x 100 = -69%
Formula
Percentage change = [(31 - 100) / 100] x 100
Subtract the new number by the original number
31 - 100 = -69
-69 ÷ 100 = -0.69
-0.69 x 100 = -69%
Example