I'm using a pivot table to compare sales data from 2004 to 2005 on a weekly
basis for several items and locations. (Location and Items are in rows,
weeks and years are in columns). By default it added a sum of the sales for
2004 and 2005 for each week. I would like to see the difference (2005 -
2004) instead. This doesn't appear to be supported by Excel.

Has anyone figured out a work-around? Or am I missing an obvious
'difference' sub-total option?