-20.22% is the change from 831 to 663
Calculation steps:
[( 663 - 831 ) ÷ 831] x 100 = -20.22%
Formula
Percentage change = [(663 - 831) / 831] x 100
Subtract the new number by the original number
663 - 831 = -168
-168 ÷ 831 = -0.20216606498194944
-0.20216606498194944 x 100 = -20.22%