-61.02% is the change from 821 to 320
Calculation steps:
[( 320 - 821 ) ÷ 821] x 100 = -61.02%
Formula
Percentage change = [(320 - 821) / 821] x 100
Subtract the new number by the original number
320 - 821 = -501
-501 ÷ 821 = -0.610231425091352
-0.610231425091352 x 100 = -61.02%