-0.15% is the change from 671 to 670
Calculation steps:
[( 670 - 671 ) ÷ 671] x 100 = -0.15%
Formula
Percentage change = [(670 - 671) / 671] x 100
Subtract the new number by the original number
670 - 671 = -1
-1 ÷ 671 = -0.0014903129657228018
-0.0014903129657228018 x 100 = -0.15%