-0.31% is the change from 649 to 647
Calculation steps:
[( 647 - 649 ) ÷ 649] x 100 = -0.31%
Formula
Percentage change = [(647 - 649) / 649] x 100
Subtract the new number by the original number
647 - 649 = -2
-2 ÷ 649 = -0.0030816640986132513
-0.0030816640986132513 x 100 = -0.31%