Not sure if what I'm trying to do is possible or if I need to change my data model.
I have a dimension containing the different amouts a customer can loan so what I wan't to do is see the share of a certain amount compared to total sales.
Pseudo code:
member [Measures].[Share 5000] as 'count([Amount].[5000])/([Measures].[Total Sales], [Time].CurrentMember)'