-90.9% is the change from 879 to 80
Calculation steps:
[( 80 - 879 ) ÷ 879] x 100 = -90.9%
Formula
Percentage change = [(80 - 879) / 879] x 100
Subtract the new number by the original number
80 - 879 = -799
-799 ÷ 879 = -0.9089874857792947
-0.9089874857792947 x 100 = -90.9%