30.93% is the change from 388 to 508
Calculation steps:
[( 508 - 388 ) ÷ 388] x 100 = 30.93%
Formula
Percentage change = [(508 - 388) / 388] x 100
Subtract the new number by the original number
508 - 388 = 120
120 ÷ 388 = 0.30927835051546393
0.30927835051546393 x 100 = 30.93%