-75.74% is the change from 639 to 155
Calculation steps:
[( 155 - 639 ) ÷ 639] x 100 = -75.74%
Formula
Percentage change = [(155 - 639) / 639] x 100
Subtract the new number by the original number
155 - 639 = -484
-484 ÷ 639 = -0.7574334898278561
-0.7574334898278561 x 100 = -75.74%