-78.2% is the change from 500 to 109
Calculation steps:
[( 109 - 500 ) ÷ 500] x 100 = -78.2%
Formula
Percentage change = [(109 - 500) / 500] x 100
Subtract the new number by the original number
109 - 500 = -391
-391 ÷ 500 = -0.782
-0.782 x 100 = -78.2%