How to find out the total number of documents exposed via Google Docs.
Goto script.google.com and start a new script and copy in the following code:
De-bug the code by pressing the "bug" button. An authorization menu will popup, that will ask permission to access Docs.
When having granted the script access to Docs, then play the script by pressing the "play" button. This might take a while, since it must read all files.
Press Ctrl + enter to view the logger (menu views/logs). Here the amount of files is displayed.