-5.09% is the change from 668 to 634
Calculation steps:
[( 634 - 668 ) ÷ 668] x 100 = -5.09%
Formula
Percentage change = [(634 - 668) / 668] x 100
Subtract the new number by the original number
634 - 668 = -34
-34 ÷ 668 = -0.05089820359281437
-0.05089820359281437 x 100 = -5.09%