-73.45% is the change from 870 to 231
Calculation steps:
[( 231 - 870 ) ÷ 870] x 100 = -73.45%
Formula
Percentage change = [(231 - 870) / 870] x 100
Subtract the new number by the original number
231 - 870 = -639
-639 ÷ 870 = -0.7344827586206897
-0.7344827586206897 x 100 = -73.45%