MDX-räkning över tid (år - inte inom ett år)

I MDX något i stil med:

with member [x] as sum( 
    [Date Dim].[CY Hierarchy].[Calendar Year].members(0) : [Date Dim].[CY Hierarchy].currentMember,
    [Measures].[Commitment Count] 
)

select [x] on 0, [Date Dim].[CY Hierarchy].[Calendar Year] on 1 from [Cube]