-98.78% is the change from 821 to 10
Calculation steps:
[( 10 - 821 ) ÷ 821] x 100 = -98.78%
Formula
Percentage change = [(10 - 821) / 821] x 100
Subtract the new number by the original number
10 - 821 = -811
-811 ÷ 821 = -0.9878197320341048
-0.9878197320341048 x 100 = -98.78%