-31.97% is the change from 638 to 434
Calculation steps:
[( 434 - 638 ) ÷ 638] x 100 = -31.97%
Formula
Percentage change = [(434 - 638) / 638] x 100
Subtract the new number by the original number
434 - 638 = -204
-204 ÷ 638 = -0.31974921630094044
-0.31974921630094044 x 100 = -31.97%