This is a fairly inelegant hack

by ReginaldVelJohnson , Friday, April 03, 2009, 08:29 (6263 days ago) @ domer.mq

But Google Spreadsheets have gadgets that can be published independently, and are updated as the original spreadsheet is changed. If all the data is in an excel sheet, it would only take updating it each week on a google spreadsheet to have a "live" pie graph.

Of course, this may be completed unrelated to what you are talking about, in which case, please ignore.