-25.4% is the change from 870 to 649
Calculation steps:
[( 649 - 870 ) ÷ 870] x 100 = -25.4%
Formula
Percentage change = [(649 - 870) / 870] x 100
Subtract the new number by the original number
649 - 870 = -221
-221 ÷ 870 = -0.2540229885057471
-0.2540229885057471 x 100 = -25.4%