-38.87% is the change from 638 to 390
Calculation steps:
[( 390 - 638 ) ÷ 638] x 100 = -38.87%
Formula
Percentage change = [(390 - 638) / 638] x 100
Subtract the new number by the original number
390 - 638 = -248
-248 ÷ 638 = -0.3887147335423197
-0.3887147335423197 x 100 = -38.87%