18.59% is the change from 538 to 638
Calculation steps:
[( 638 - 538 ) ÷ 538] x 100 = 18.59%
Formula
Percentage change = [(638 - 538) / 538] x 100
Subtract the new number by the original number
638 - 538 = 100
100 ÷ 538 = 0.18587360594795538
0.18587360594795538 x 100 = 18.59%