I don't know of any specific tool  but you can do this yourself. Just
click on the web folder for your workspace  and right click on the
documents folder. The number  of files and folders comes up. As this is
an intensive thing it will take sometime to show you the values. There's
no one query I know of that will do this so you have to physically count
them. I wrote a small vb script to do this but even without any output
(except the final result) it still took about 5 minutes with only 5gb of
data.