-9% is the change from 878 to 799
Calculation steps:
[( 799 - 878 ) ÷ 878] x 100 = -9%
Formula
Percentage change = [(799 - 878) / 878] x 100
Subtract the new number by the original number
799 - 878 = -79
-79 ÷ 878 = -0.08997722095671981
-0.08997722095671981 x 100 = -9%