-49.37% is the change from 638 to 323
Calculation steps:
[( 323 - 638 ) ÷ 638] x 100 = -49.37%
Formula
Percentage change = [(323 - 638) / 638] x 100
Subtract the new number by the original number
323 - 638 = -315
-315 ÷ 638 = -0.493730407523511
-0.493730407523511 x 100 = -49.37%