50% is the change from 426 to 639
Calculation steps:
[( 639 - 426 ) ÷ 426] x 100 = 50%
Formula
Percentage change = [(639 - 426) / 426] x 100
Subtract the new number by the original number
639 - 426 = 213
213 ÷ 426 = 0.5
0.5 x 100 = 50%
Example