-38.39% is the change from 831 to 512
Calculation steps:
[( 512 - 831 ) ÷ 831] x 100 = -38.39%
Formula
Percentage change = [(512 - 831) / 831] x 100
Subtract the new number by the original number
512 - 831 = -319
-319 ÷ 831 = -0.3838748495788207
-0.3838748495788207 x 100 = -38.39%