-81.59% is the change from 668 to 123
Calculation steps:
[( 123 - 668 ) ÷ 668] x 100 = -81.59%
Formula
Percentage change = [(123 - 668) / 668] x 100
Subtract the new number by the original number
123 - 668 = -545
-545 ÷ 668 = -0.8158682634730539
-0.8158682634730539 x 100 = -81.59%