-39.84% is the change from 512 to 308
Calculation steps:
[( 308 - 512 ) ÷ 512] x 100 = -39.84%
Formula
Percentage change = [(308 - 512) / 512] x 100
Subtract the new number by the original number
308 - 512 = -204
-204 ÷ 512 = -0.3984375
-0.3984375 x 100 = -39.84%