-23.63% is the change from 512 to 391
Calculation steps:
[( 391 - 512 ) ÷ 512] x 100 = -23.63%
Formula
Percentage change = [(391 - 512) / 512] x 100
Subtract the new number by the original number
391 - 512 = -121
-121 ÷ 512 = -0.236328125
-0.236328125 x 100 = -23.63%