-0.9% is the change from 668 to 662
Calculation steps:
[( 662 - 668 ) ÷ 668] x 100 = -0.9%
Formula
Percentage change = [(662 - 668) / 668] x 100
Subtract the new number by the original number
662 - 668 = -6
-6 ÷ 668 = -0.008982035928143712
-0.008982035928143712 x 100 = -0.9%