-31.52% is the change from 939 to 643
Calculation steps:
[( 643 - 939 ) ÷ 939] x 100 = -31.52%
Formula
Percentage change = [(643 - 939) / 939] x 100
Subtract the new number by the original number
643 - 939 = -296
-296 ÷ 939 = -0.3152289669861555
-0.3152289669861555 x 100 = -31.52%