-40.84% is the change from 830 to 491
Calculation steps:
[( 491 - 830 ) ÷ 830] x 100 = -40.84%
Formula
Percentage change = [(491 - 830) / 830] x 100
Subtract the new number by the original number
491 - 830 = -339
-339 ÷ 830 = -0.40843373493975904
-0.40843373493975904 x 100 = -40.84%