51.25% is the change from 640 to 968
Calculation steps:
[( 968 - 640 ) ÷ 640] x 100 = 51.25%
Formula
Percentage change = [(968 - 640) / 640] x 100
Subtract the new number by the original number
968 - 640 = 328
328 ÷ 640 = 0.5125
0.5125 x 100 = 51.25%