19.89% is the change from 538 to 645
Calculation steps:
[( 645 - 538 ) ÷ 538] x 100 = 19.89%
Formula
Percentage change = [(645 - 538) / 538] x 100
Subtract the new number by the original number
645 - 538 = 107
107 ÷ 538 = 0.19888475836431227
0.19888475836431227 x 100 = 19.89%