-86.99% is the change from 638 to 83
Calculation steps:
[( 83 - 638 ) ÷ 638] x 100 = -86.99%
Formula
Percentage change = [(83 - 638) / 638] x 100
Subtract the new number by the original number
83 - 638 = -555
-555 ÷ 638 = -0.8699059561128527
-0.8699059561128527 x 100 = -86.99%