-39.06% is the change from 512 to 312
Calculation steps:
[( 312 - 512 ) ÷ 512] x 100 = -39.06%
Formula
Percentage change = [(312 - 512) / 512] x 100
Subtract the new number by the original number
312 - 512 = -200
-200 ÷ 512 = -0.390625
-0.390625 x 100 = -39.06%