-9.1% is the change from 879 to 799
Calculation steps:
[( 799 - 879 ) ÷ 879] x 100 = -9.1%
Formula
Percentage change = [(799 - 879) / 879] x 100
Subtract the new number by the original number
799 - 879 = -80
-80 ÷ 879 = -0.09101251422070535
-0.09101251422070535 x 100 = -9.1%