-55.06% is the change from 870 to 391
Calculation steps:
[( 391 - 870 ) ÷ 870] x 100 = -55.06%
Formula
Percentage change = [(391 - 870) / 870] x 100
Subtract the new number by the original number
391 - 870 = -479
-479 ÷ 870 = -0.5505747126436782
-0.5505747126436782 x 100 = -55.06%