-3.1% is the change from 646 to 626
Calculation steps:
[( 626 - 646 ) ÷ 646] x 100 = -3.1%
Formula
Percentage change = [(626 - 646) / 646] x 100
Subtract the new number by the original number
626 - 646 = -20
-20 ÷ 646 = -0.030959752321981424
-0.030959752321981424 x 100 = -3.1%