-39.75% is the change from 649 to 391
Calculation steps:
[( 391 - 649 ) ÷ 649] x 100 = -39.75%
Formula
Percentage change = [(391 - 649) / 649] x 100
Subtract the new number by the original number
391 - 649 = -258
-258 ÷ 649 = -0.3975346687211094
-0.3975346687211094 x 100 = -39.75%