21.75% is the change from 639 to 778
Calculation steps:
[( 778 - 639 ) ÷ 639] x 100 = 21.75%
Formula
Percentage change = [(778 - 639) / 639] x 100
Subtract the new number by the original number
778 - 639 = 139
139 ÷ 639 = 0.21752738654147105
0.21752738654147105 x 100 = 21.75%