-90.34% is the change from 870 to 84
Calculation steps:
[( 84 - 870 ) ÷ 870] x 100 = -90.34%
Formula
Percentage change = [(84 - 870) / 870] x 100
Subtract the new number by the original number
84 - 870 = -786
-786 ÷ 870 = -0.903448275862069
-0.903448275862069 x 100 = -90.34%