-0.15% is the change from 669 to 668
Calculation steps:
[( 668 - 669 ) ÷ 669] x 100 = -0.15%
Formula
Percentage change = [(668 - 669) / 669] x 100
Subtract the new number by the original number
668 - 669 = -1
-1 ÷ 669 = -0.0014947683109118087
-0.0014947683109118087 x 100 = -0.15%