-23.83% is the change from 512 to 390
Calculation steps:
[( 390 - 512 ) ÷ 512] x 100 = -23.83%
Formula
Percentage change = [(390 - 512) / 512] x 100
Subtract the new number by the original number
390 - 512 = -122
-122 ÷ 512 = -0.23828125
-0.23828125 x 100 = -23.83%