-3.17% is the change from 631 to 611
Calculation steps:
[( 611 - 631 ) ÷ 631] x 100 = -3.17%
Formula
Percentage change = [(611 - 631) / 631] x 100
Subtract the new number by the original number
611 - 631 = -20
-20 ÷ 631 = -0.03169572107765452
-0.03169572107765452 x 100 = -3.17%