Calculate and display a ratio between two datasources

Hi gurus,

In SAP Design Studio 1.2, I've 2 datasources :

- One filtered on "Current year"

- Another filtered on "Last Year"

My question is : I'm trying to view a ratio which is "Measure(CurrentYear)/Measure(LastYear)" in a crosstab or a simple text area and I don't know how to cross datasources and create a variable !

Can we do that and mainly, can you do that and explain ?

Any help appreciated.

Regards,

William