-2.99% is the change from 668 to 648
Calculation steps:
[( 648 - 668 ) ÷ 668] x 100 = -2.99%
Formula
Percentage change = [(648 - 668) / 668] x 100
Subtract the new number by the original number
648 - 668 = -20
-20 ÷ 668 = -0.029940119760479042
-0.029940119760479042 x 100 = -2.99%