-39.55% is the change from 842 to 509
Calculation steps:
[( 509 - 842 ) ÷ 842] x 100 = -39.55%
Formula
Percentage change = [(509 - 842) / 842] x 100
Subtract the new number by the original number
509 - 842 = -333
-333 ÷ 842 = -0.39548693586698336
-0.39548693586698336 x 100 = -39.55%