-87.56% is the change from 820 to 102
Calculation steps:
[( 102 - 820 ) ÷ 820] x 100 = -87.56%
Formula
Percentage change = [(102 - 820) / 820] x 100
Subtract the new number by the original number
102 - 820 = -718
-718 ÷ 820 = -0.875609756097561
-0.875609756097561 x 100 = -87.56%