-84.36% is the change from 518 to 81
Calculation steps:
[( 81 - 518 ) ÷ 518] x 100 = -84.36%
Formula
Percentage change = [(81 - 518) / 518] x 100
Subtract the new number by the original number
81 - 518 = -437
-437 ÷ 518 = -0.8436293436293436
-0.8436293436293436 x 100 = -84.36%