-28.74% is the change from 870 to 620
Calculation steps:
[( 620 - 870 ) ÷ 870] x 100 = -28.74%
Formula
Percentage change = [(620 - 870) / 870] x 100
Subtract the new number by the original number
620 - 870 = -250
-250 ÷ 870 = -0.28735632183908044
-0.28735632183908044 x 100 = -28.74%