50% is the change from 206 to 309
Calculation steps:
[( 309 - 206 ) ÷ 206] x 100 = 50%
Formula
Percentage change = [(309 - 206) / 206] x 100
Subtract the new number by the original number
309 - 206 = 103
103 ÷ 206 = 0.5
0.5 x 100 = 50%
Example