2.36% is the change from 509 to 521
Calculation steps:
[( 521 - 509 ) ÷ 509] x 100 = 2.36%
Formula
Percentage change = [(521 - 509) / 509] x 100
Subtract the new number by the original number
521 - 509 = 12
12 ÷ 509 = 0.023575638506876228
0.023575638506876228 x 100 = 2.36%