-27.42% is the change from 879 to 638
Calculation steps:
[( 638 - 879 ) ÷ 879] x 100 = -27.42%
Formula
Percentage change = [(638 - 879) / 879] x 100
Subtract the new number by the original number
638 - 879 = -241
-241 ÷ 879 = -0.27417519908987487
-0.27417519908987487 x 100 = -27.42%