-89.76% is the change from 820 to 84
Calculation steps:
[( 84 - 820 ) ÷ 820] x 100 = -89.76%
Formula
Percentage change = [(84 - 820) / 820] x 100
Subtract the new number by the original number
84 - 820 = -736
-736 ÷ 820 = -0.8975609756097561
-0.8975609756097561 x 100 = -89.76%