50% is the change from 204 to 306
Calculation steps:
[( 306 - 204 ) ÷ 204] x 100 = 50%
Formula
Percentage change = [(306 - 204) / 204] x 100
Subtract the new number by the original number
306 - 204 = 102
102 ÷ 204 = 0.5
0.5 x 100 = 50%
Example