-40.47% is the change from 855 to 509
Calculation steps:
[( 509 - 855 ) ÷ 855] x 100 = -40.47%
Formula
Percentage change = [(509 - 855) / 855] x 100
Subtract the new number by the original number
509 - 855 = -346
-346 ÷ 855 = -0.4046783625730994
-0.4046783625730994 x 100 = -40.47%