-40.12% is the change from 855 to 512
Calculation steps:
[( 512 - 855 ) ÷ 855] x 100 = -40.12%
Formula
Percentage change = [(512 - 855) / 855] x 100
Subtract the new number by the original number
512 - 855 = -343
-343 ÷ 855 = -0.40116959064327484
-0.40116959064327484 x 100 = -40.12%