-84.21% is the change from 513 to 81
Calculation steps:
[( 81 - 513 ) ÷ 513] x 100 = -84.21%
Formula
Percentage change = [(81 - 513) / 513] x 100
Subtract the new number by the original number
81 - 513 = -432
-432 ÷ 513 = -0.8421052631578947
-0.8421052631578947 x 100 = -84.21%