-20.57% is the change from 870 to 691
Calculation steps:
[( 691 - 870 ) ÷ 870] x 100 = -20.57%
Formula
Percentage change = [(691 - 870) / 870] x 100
Subtract the new number by the original number
691 - 870 = -179
-179 ÷ 870 = -0.2057471264367816
-0.2057471264367816 x 100 = -20.57%