-57.51% is the change from 939 to 399
Calculation steps:
[( 399 - 939 ) ÷ 939] x 100 = -57.51%
Formula
Percentage change = [(399 - 939) / 939] x 100
Subtract the new number by the original number
399 - 939 = -540
-540 ÷ 939 = -0.5750798722044729
-0.5750798722044729 x 100 = -57.51%