-74.39% is the change from 820 to 210
Calculation steps:
[( 210 - 820 ) ÷ 820] x 100 = -74.39%
Formula
Percentage change = [(210 - 820) / 820] x 100
Subtract the new number by the original number
210 - 820 = -610
-610 ÷ 820 = -0.7439024390243902
-0.7439024390243902 x 100 = -74.39%