-37.3% is the change from 638 to 400
Calculation steps:
[( 400 - 638 ) ÷ 638] x 100 = -37.3%
Formula
Percentage change = [(400 - 638) / 638] x 100
Subtract the new number by the original number
400 - 638 = -238
-238 ÷ 638 = -0.3730407523510972
-0.3730407523510972 x 100 = -37.3%