Pivot table displaying value as percentage of another value

So I've got a script that runs and collects data on all of our data servers. It runs once a week and puts this in a SQL database. I then grab this data with Excel. The header rows are Hostname, DriveName, TotalCapacity, FreeSpace, UsedSpace, and DateScanned. The goal is to be able to show capacity changes from week to week. Now unless we add disk to a server, the totalCapacity field rarely changes for each server, but it does happen.

What I'd like to do is use a pivot table to show something like.

Hostname 1/7/2011 1/14/011 1/21/2011
ServerA
-C: Drive 50% 51% 51%
-D: Drive 25% 30% 50%
-E: Drive 80% 90% 99%
ServerB
-C: Drive 50% 51% 55%
-D: Drive 50% 55% 60%

Essentially I'd like to display the UsedSpace value as a percentage of the TotalCapacity value, but I can never get it to display properly. It always want's it to base it off a specific cell value, or either previous or next which doesn't work either. Does anyone know how I set this up?

Ok here's a small snippet. There is one more field - TempID, but that's just for SQL, you can ignore it completely.

Awesome! This is exactly what I was looking for. Thank you so much for the help!

Cheeky Charlie Thank you so much for this solution, I have been cudgelling my brains, added dozens of columns with % to solve a similar problem, but now I found it! THANK YOU MAN!