-97.07% is the change from 512 to 15
Calculation steps:
[( 15 - 512 ) ÷ 512] x 100 = -97.07%
Formula
Percentage change = [(15 - 512) / 512] x 100
Subtract the new number by the original number
15 - 512 = -497
-497 ÷ 512 = -0.970703125
-0.970703125 x 100 = -97.07%