4.08% is the change from 638 to 664
Calculation steps:
[( 664 - 638 ) ÷ 638] x 100 = 4.08%
Formula
Percentage change = [(664 - 638) / 638] x 100
Subtract the new number by the original number
664 - 638 = 26
26 ÷ 638 = 0.04075235109717868
0.04075235109717868 x 100 = 4.08%