-80.92% is the change from 519 to 99
Calculation steps:
[( 99 - 519 ) ÷ 519] x 100 = -80.92%
Formula
Percentage change = [(99 - 519) / 519] x 100
Subtract the new number by the original number
99 - 519 = -420
-420 ÷ 519 = -0.8092485549132948
-0.8092485549132948 x 100 = -80.92%
Example