-80.66% is the change from 512 to 99
Calculation steps:
[( 99 - 512 ) ÷ 512] x 100 = -80.66%
Formula
Percentage change = [(99 - 512) / 512] x 100
Subtract the new number by the original number
99 - 512 = -413
-413 ÷ 512 = -0.806640625
-0.806640625 x 100 = -80.66%