[Google-Desktop-Developer] How do the "Sort by relevance" feature in GD work?

Hi,

I am currently using Google Desktop (GD) APIs for my software
application. I meet with the problem that the relevancy score is not
returned in the XML format of the results returned by GD. I am required

to display the relevancy score to the user.

Therefore, I would like to ask the Google Desktop team or anyone who is

kind enough to provide me with the information on calculation of the
relevancy score?

Thanks a lot for your help...

regard,
Kelvin Ang