98.05% is the change from 257 to 509
Calculation steps:
[( 509 - 257 ) ÷ 257] x 100 = 98.05%
Formula
Percentage change = [(509 - 257) / 257] x 100
Subtract the new number by the original number
509 - 257 = 252
252 ÷ 257 = 0.980544747081712
0.980544747081712 x 100 = 98.05%