-1.71% is the change from 642 to 631
Calculation steps:
[( 631 - 642 ) ÷ 642] x 100 = -1.71%
Formula
Percentage change = [(631 - 642) / 642] x 100
Subtract the new number by the original number
631 - 642 = -11
-11 ÷ 642 = -0.017133956386292833
-0.017133956386292833 x 100 = -1.71%