-82.8% is the change from 500 to 86
Calculation steps:
[( 86 - 500 ) ÷ 500] x 100 = -82.8%
Formula
Percentage change = [(86 - 500) / 500] x 100
Subtract the new number by the original number
86 - 500 = -414
-414 ÷ 500 = -0.828
-0.828 x 100 = -82.8%
Example