-1.2% is the change from 668 to 660
Calculation steps:
[( 660 - 668 ) ÷ 668] x 100 = -1.2%
Formula
Percentage change = [(660 - 668) / 668] x 100
Subtract the new number by the original number
660 - 668 = -8
-8 ÷ 668 = -0.011976047904191617
-0.011976047904191617 x 100 = -1.2%