30.69% is the change from 642 to 839
Calculation steps:
[( 839 - 642 ) ÷ 642] x 100 = 30.69%
Formula
Percentage change = [(839 - 642) / 642] x 100
Subtract the new number by the original number
839 - 642 = 197
197 ÷ 642 = 0.3068535825545171
0.3068535825545171 x 100 = 30.69%