-51.72% is the change from 638 to 308
Calculation steps:
[( 308 - 638 ) ÷ 638] x 100 = -51.72%
Formula
Percentage change = [(308 - 638) / 638] x 100
Subtract the new number by the original number
308 - 638 = -330
-330 ÷ 638 = -0.5172413793103449
-0.5172413793103449 x 100 = -51.72%