-79.47% is the change from 638 to 131
Calculation steps:
[( 131 - 638 ) ÷ 638] x 100 = -79.47%
Formula
Percentage change = [(131 - 638) / 638] x 100
Subtract the new number by the original number
131 - 638 = -507
-507 ÷ 638 = -0.7946708463949843
-0.7946708463949843 x 100 = -79.47%