3.74% is the change from 615 to 638
Calculation steps:
[( 638 - 615 ) ÷ 615] x 100 = 3.74%
Formula
Percentage change = [(638 - 615) / 615] x 100
Subtract the new number by the original number
638 - 615 = 23
23 ÷ 615 = 0.03739837398373984
0.03739837398373984 x 100 = 3.74%