-49.61% is the change from 512 to 258
Calculation steps:
[( 258 - 512 ) ÷ 512] x 100 = -49.61%
Formula
Percentage change = [(258 - 512) / 512] x 100
Subtract the new number by the original number
258 - 512 = -254
-254 ÷ 512 = -0.49609375
-0.49609375 x 100 = -49.61%