4.7% is the change from 638 to 668
Calculation steps:
[( 668 - 638 ) ÷ 638] x 100 = 4.7%
Formula
Percentage change = [(668 - 638) / 638] x 100
Subtract the new number by the original number
668 - 638 = 30
30 ÷ 638 = 0.047021943573667714
0.047021943573667714 x 100 = 4.7%