-83.86% is the change from 502 to 81
Calculation steps:
[( 81 - 502 ) ÷ 502] x 100 = -83.86%
Formula
Percentage change = [(81 - 502) / 502] x 100
Subtract the new number by the original number
81 - 502 = -421
-421 ÷ 502 = -0.8386454183266933
-0.8386454183266933 x 100 = -83.86%