-70.57% is the change from 870 to 256
Calculation steps:
[( 256 - 870 ) ÷ 870] x 100 = -70.57%
Formula
Percentage change = [(256 - 870) / 870] x 100
Subtract the new number by the original number
256 - 870 = -614
-614 ÷ 870 = -0.7057471264367816
-0.7057471264367816 x 100 = -70.57%