-51.1% is the change from 638 to 312
Calculation steps:
[( 312 - 638 ) ÷ 638] x 100 = -51.1%
Formula
Percentage change = [(312 - 638) / 638] x 100
Subtract the new number by the original number
312 - 638 = -326
-326 ÷ 638 = -0.5109717868338558
-0.5109717868338558 x 100 = -51.1%