-64.37% is the change from 870 to 310
Calculation steps:
[( 310 - 870 ) ÷ 870] x 100 = -64.37%
Formula
Percentage change = [(310 - 870) / 870] x 100
Subtract the new number by the original number
310 - 870 = -560
-560 ÷ 870 = -0.6436781609195402
-0.6436781609195402 x 100 = -64.37%