You can find what is stored by looking at the document type for the page(menu item) and going to the fields. On the fields, the field MenuItemGroup will have the values and the first items in the box are the values that are stored.
The values in the field by default are:(value, text)
Does your where clause look like this:
So just make sure that your documents have that footer option selected and see if that fixes anything. Also as Brenden suggested, make sure the documents are published. They must have the green icon, otherwise, the document isn't published and won't show in the list.