-51.88% is the change from 638 to 307
Calculation steps:
[( 307 - 638 ) ÷ 638] x 100 = -51.88%
Formula
Percentage change = [(307 - 638) / 638] x 100
Subtract the new number by the original number
307 - 638 = -331
-331 ÷ 638 = -0.5188087774294671
-0.5188087774294671 x 100 = -51.88%