Calculated Key figure?!

I have to report in which i need to report the year-over-year change of a KF as a separate column.

The report (simplified here) has product (characteristic) as rows, the columns are Revenue (KF) -> Year (characteristic)

How can i add an extra calculated column in the report so that it shows the results by calculating "100 * Revenue(2011)/Revenue(2010)". The report format will be something like this -

Revenue

2010 2011 Y-O-Y

Product1 100 120 20%

Product2 200 250 25%

Any ideas?