-13.8% is the change from 500 to 431
Calculation steps:
[( 431 - 500 ) ÷ 500] x 100 = -13.8%
Formula
Percentage change = [(431 - 500) / 500] x 100
Subtract the new number by the original number
431 - 500 = -69
-69 ÷ 500 = -0.138
-0.138 x 100 = -13.8%