3.67% is the change from 491 to 509
Calculation steps:
[( 509 - 491 ) ÷ 491] x 100 = 3.67%
Formula
Percentage change = [(509 - 491) / 491] x 100
Subtract the new number by the original number
509 - 491 = 18
18 ÷ 491 = 0.03665987780040733
0.03665987780040733 x 100 = 3.67%