-79.27% is the change from 820 to 170
Calculation steps:
[( 170 - 820 ) ÷ 820] x 100 = -79.27%
Formula
Percentage change = [(170 - 820) / 820] x 100
Subtract the new number by the original number
170 - 820 = -650
-650 ÷ 820 = -0.7926829268292683
-0.7926829268292683 x 100 = -79.27%