63.06% is the change from 509 to 830
Calculation steps:
[( 830 - 509 ) ÷ 509] x 100 = 63.06%
Formula
Percentage change = [(830 - 509) / 509] x 100
Subtract the new number by the original number
830 - 509 = 321
321 ÷ 509 = 0.630648330058939
0.630648330058939 x 100 = 63.06%