-13.6% is the change from 581 to 502
Calculation steps:
[( 502 - 581 ) ÷ 581] x 100 = -13.6%
Formula
Percentage change = [(502 - 581) / 581] x 100
Subtract the new number by the original number
502 - 581 = -79
-79 ÷ 581 = -0.1359724612736661
-0.1359724612736661 x 100 = -13.6%