-81.11% is the change from 831 to 157
Calculation steps:
[( 157 - 831 ) ÷ 831] x 100 = -81.11%
Formula
Percentage change = [(157 - 831) / 831] x 100
Subtract the new number by the original number
157 - 831 = -674
-674 ÷ 831 = -0.8110709987966306
-0.8110709987966306 x 100 = -81.11%