-37.62% is the change from 638 to 398
Calculation steps:
[( 398 - 638 ) ÷ 638] x 100 = -37.62%
Formula
Percentage change = [(398 - 638) / 638] x 100
Subtract the new number by the original number
398 - 638 = -240
-240 ÷ 638 = -0.3761755485893417
-0.3761755485893417 x 100 = -37.62%