how to view where Google Custom Search get's it's autocomplete data from, and can you add this data automatically?

I have implemented the Google Custom Search Engine on my site and it works, however the results that it is returning within the autocomplete are very limited and not very useful. Does anyone know how to find where it is getting the data for the autocomplete functionality, and if there is a way to add to this list automatically, and not via the 'add custom autocompletions' or upload XML within the autocomplete tab on the custom search engine config dashboard. Thanks.