You can do this by using Average of Number of Records and placing it for the number of columns you'd like to see. Right click on each instance and choose Text as the mark type. Then, on the marks card put the desired measure on the text shelf. For the last column, create a dual axis, with two instances of Avg(Number of Records). Right click on each and give one the mark type of shape and the other as text. I have attached a sample workbook.
Hope this helps!
Thanks a lot Tracy, it works properly.
A possible issue with the solution you offered is that the text isn't exactly aligned within the columns, you can see this in the 2nd column, Category: Furniture, Sub-Category: Tables. It was dealing with issues like this that led me to create the http://public.tableausoftware.com/views/conditionalformattingv4/Introduction workbook. Instead of using AVG(Number of Records), using a MIN(0.0) or MIN(1.0) measure along with fixed axes gives more control over alignment.
I was actually looking for your workbook to send on, but couldn't find it! This was a workbook that I've had for awhile--so I hadn't updated it. Thanks for looking out and posting this Jonathan!