-19.16% is the change from 668 to 540
Calculation steps:
[( 540 - 668 ) ÷ 668] x 100 = -19.16%
Formula
Percentage change = [(540 - 668) / 668] x 100
Subtract the new number by the original number
540 - 668 = -128
-128 ÷ 668 = -0.19161676646706588
-0.19161676646706588 x 100 = -19.16%