-3.09% is the change from 518 to 502
Calculation steps:
[( 502 - 518 ) ÷ 518] x 100 = -3.09%
Formula
Percentage change = [(502 - 518) / 518] x 100
Subtract the new number by the original number
502 - 518 = -16
-16 ÷ 518 = -0.03088803088803089
-0.03088803088803089 x 100 = -3.09%