-37.46% is the change from 638 to 399
Calculation steps:
[( 399 - 638 ) ÷ 638] x 100 = -37.46%
Formula
Percentage change = [(399 - 638) / 638] x 100
Subtract the new number by the original number
399 - 638 = -239
-239 ÷ 638 = -0.37460815047021945
-0.37460815047021945 x 100 = -37.46%