-85.17% is the change from 870 to 129
Calculation steps:
[( 129 - 870 ) ÷ 870] x 100 = -85.17%
Formula
Percentage change = [(129 - 870) / 870] x 100
Subtract the new number by the original number
129 - 870 = -741
-741 ÷ 870 = -0.8517241379310345
-0.8517241379310345 x 100 = -85.17%