-26.78% is the change from 870 to 637
Calculation steps:
[( 637 - 870 ) ÷ 870] x 100 = -26.78%
Formula
Percentage change = [(637 - 870) / 870] x 100
Subtract the new number by the original number
637 - 870 = -233
-233 ÷ 870 = -0.267816091954023
-0.267816091954023 x 100 = -26.78%