65.05% is the change from 309 to 510
Calculation steps:
[( 510 - 309 ) ÷ 309] x 100 = 65.05%
Formula
Percentage change = [(510 - 309) / 309] x 100
Subtract the new number by the original number
510 - 309 = 201
201 ÷ 309 = 0.6504854368932039
0.6504854368932039 x 100 = 65.05%