-21.84% is the change from 870 to 680
Calculation steps:
[( 680 - 870 ) ÷ 870] x 100 = -21.84%
Formula
Percentage change = [(680 - 870) / 870] x 100
Subtract the new number by the original number
680 - 870 = -190
-190 ÷ 870 = -0.21839080459770116
-0.21839080459770116 x 100 = -21.84%