55.78% is the change from 640 to 997
Calculation steps:
[( 997 - 640 ) ÷ 640] x 100 = 55.78%
Formula
Percentage change = [(997 - 640) / 640] x 100
Subtract the new number by the original number
997 - 640 = 357
357 ÷ 640 = 0.5578125
0.5578125 x 100 = 55.78%