-86.72% is the change from 821 to 109
Calculation steps:
[( 109 - 821 ) ÷ 821] x 100 = -86.72%
Formula
Percentage change = [(109 - 821) / 821] x 100
Subtract the new number by the original number
109 - 821 = -712
-712 ÷ 821 = -0.8672350791717418
-0.8672350791717418 x 100 = -86.72%