You haven't uploaded any documents into your account. You are using the built-in lyrics field, which is not included in the count of documents. (Actually it is in the apps, which I'll fix.) To check for missing lyrics, the smart lists would need an option for checking the contents of the Lyrics field, which I'll put on my wish list. Meanwhile, you can look at any song list for the document icon, which indicates the presence or absence of lyrics in your account since you aren't using documents.