-40.12% is the change from 668 to 400
Calculation steps:
[( 400 - 668 ) ÷ 668] x 100 = -40.12%
Formula
Percentage change = [(400 - 668) / 668] x 100
Subtract the new number by the original number
400 - 668 = -268
-268 ÷ 668 = -0.40119760479041916
-0.40119760479041916 x 100 = -40.12%