-3.87% is the change from 646 to 621
Calculation steps:
[( 621 - 646 ) ÷ 646] x 100 = -3.87%
Formula
Percentage change = [(621 - 646) / 646] x 100
Subtract the new number by the original number
621 - 646 = -25
-25 ÷ 646 = -0.03869969040247678
-0.03869969040247678 x 100 = -3.87%