-1.38% is the change from 509 to 502
Calculation steps:
[( 502 - 509 ) ÷ 509] x 100 = -1.38%
Formula
Percentage change = [(502 - 509) / 509] x 100
Subtract the new number by the original number
502 - 509 = -7
-7 ÷ 509 = -0.0137524557956778
-0.0137524557956778 x 100 = -1.38%