30.08% is the change from 645 to 839
Calculation steps:
[( 839 - 645 ) ÷ 645] x 100 = 30.08%
Formula
Percentage change = [(839 - 645) / 645] x 100
Subtract the new number by the original number
839 - 645 = 194
194 ÷ 645 = 0.30077519379844964
0.30077519379844964 x 100 = 30.08%