-19.27% is the change from 820 to 662
Calculation steps:
[( 662 - 820 ) ÷ 820] x 100 = -19.27%
Formula
Percentage change = [(662 - 820) / 820] x 100
Subtract the new number by the original number
662 - 820 = -158
-158 ÷ 820 = -0.1926829268292683
-0.1926829268292683 x 100 = -19.27%