-39.52% is the change from 830 to 502
Calculation steps:
[( 502 - 830 ) ÷ 830] x 100 = -39.52%
Formula
Percentage change = [(502 - 830) / 830] x 100
Subtract the new number by the original number
502 - 830 = -328
-328 ÷ 830 = -0.39518072289156625
-0.39518072289156625 x 100 = -39.52%