-23.22% is the change from 870 to 668
Calculation steps:
[( 668 - 870 ) ÷ 870] x 100 = -23.22%
Formula
Percentage change = [(668 - 870) / 870] x 100
Subtract the new number by the original number
668 - 870 = -202
-202 ÷ 870 = -0.23218390804597702
-0.23218390804597702 x 100 = -23.22%