-50.69% is the change from 649 to 320
Calculation steps:
[( 320 - 649 ) ÷ 649] x 100 = -50.69%
Formula
Percentage change = [(320 - 649) / 649] x 100
Subtract the new number by the original number
320 - 649 = -329
-329 ÷ 649 = -0.5069337442218799
-0.5069337442218799 x 100 = -50.69%