19.57% is the change from 644 to 770
Calculation steps:
[( 770 - 644 ) ÷ 644] x 100 = 19.57%
Formula
Percentage change = [(770 - 644) / 644] x 100
Subtract the new number by the original number
770 - 644 = 126
126 ÷ 644 = 0.1956521739130435
0.1956521739130435 x 100 = 19.57%