-87.9% is the change from 818 to 99
Calculation steps:
[( 99 - 818 ) ÷ 818] x 100 = -87.9%
Formula
Percentage change = [(99 - 818) / 818] x 100
Subtract the new number by the original number
99 - 818 = -719
-719 ÷ 818 = -0.8789731051344744
-0.8789731051344744 x 100 = -87.9%