-22.99% is the change from 870 to 670
Calculation steps:
[( 670 - 870 ) ÷ 870] x 100 = -22.99%
Formula
Percentage change = [(670 - 870) / 870] x 100
Subtract the new number by the original number
670 - 870 = -200
-200 ÷ 870 = -0.22988505747126436
-0.22988505747126436 x 100 = -22.99%