-3.13% is the change from 639 to 619
Calculation steps:
[( 619 - 639 ) ÷ 639] x 100 = -3.13%
Formula
Percentage change = [(619 - 639) / 639] x 100
Subtract the new number by the original number
619 - 639 = -20
-20 ÷ 639 = -0.03129890453834116
-0.03129890453834116 x 100 = -3.13%