I'm still thinking in SQL terms.. and so what I want to do is this... in MDX... (I know the syntax below won't work but im just trying to illustrate the point).

declare @CYear varchar(10)

set @CYear = '2012/2013'

begin

select datepart(year, dueDate), count(*)

from [AdventureWorksDW2012].[dbo].[FactInternetSales]

where datepart(year, dueDate) between @CYear and (@CYear -2)

group by datepart(year, dueDate)

end ;

Ideally i'd like to derive the current period from within the query from the cube.