-87.58% is the change from 821 to 102
Calculation steps:
[( 102 - 821 ) ÷ 821] x 100 = -87.58%
Formula
Percentage change = [(102 - 821) / 821] x 100
Subtract the new number by the original number
102 - 821 = -719
-719 ÷ 821 = -0.8757612667478685
-0.8757612667478685 x 100 = -87.58%