-6.6% is the change from 879 to 821
Calculation steps:
[( 821 - 879 ) ÷ 879] x 100 = -6.6%
Formula
Percentage change = [(821 - 879) / 879] x 100
Subtract the new number by the original number
821 - 879 = -58
-58 ÷ 879 = -0.06598407281001138
-0.06598407281001138 x 100 = -6.6%