-80.47% is the change from 512 to 100
Calculation steps:
[( 100 - 512 ) ÷ 512] x 100 = -80.47%
Formula
Percentage change = [(100 - 512) / 512] x 100
Subtract the new number by the original number
100 - 512 = -412
-412 ÷ 512 = -0.8046875
-0.8046875 x 100 = -80.47%