21.41% is the change from 640 to 777
Calculation steps:
[( 777 - 640 ) ÷ 640] x 100 = 21.41%
Formula
Percentage change = [(777 - 640) / 640] x 100
Subtract the new number by the original number
777 - 640 = 137
137 ÷ 640 = 0.2140625
0.2140625 x 100 = 21.41%