-76.11% is the change from 339 to 81
Calculation steps:
[( 81 - 339 ) ÷ 339] x 100 = -76.11%
Formula
Percentage change = [(81 - 339) / 339] x 100
Subtract the new number by the original number
81 - 339 = -258
-258 ÷ 339 = -0.7610619469026548
-0.7610619469026548 x 100 = -76.11%