-99.39% is the change from 820 to 5
Calculation steps:
[( 5 - 820 ) ÷ 820] x 100 = -99.39%
Formula
Percentage change = [(5 - 820) / 820] x 100
Subtract the new number by the original number
5 - 820 = -815
-815 ÷ 820 = -0.9939024390243902
-0.9939024390243902 x 100 = -99.39%