-61.68% is the change from 668 to 256
Calculation steps:
[( 256 - 668 ) ÷ 668] x 100 = -61.68%
Formula
Percentage change = [(256 - 668) / 668] x 100
Subtract the new number by the original number
256 - 668 = -412
-412 ÷ 668 = -0.6167664670658682
-0.6167664670658682 x 100 = -61.68%