30.88% is the change from 638 to 835
Calculation steps:
[( 835 - 638 ) ÷ 638] x 100 = 30.88%
Formula
Percentage change = [(835 - 638) / 638] x 100
Subtract the new number by the original number
835 - 638 = 197
197 ÷ 638 = 0.30877742946708464
0.30877742946708464 x 100 = 30.88%