-26.32% is the change from 870 to 641
Calculation steps:
[( 641 - 870 ) ÷ 870] x 100 = -26.32%
Formula
Percentage change = [(641 - 870) / 870] x 100
Subtract the new number by the original number
641 - 870 = -229
-229 ÷ 870 = -0.2632183908045977
-0.2632183908045977 x 100 = -26.32%