percent-of-total calculated measure in MS AS

[dazzlah]

Hi All,

In MS Analyssis Services I am looking for a way to create a calculated measure that will provide a market-share value, which is basically a percent of total for each member of a dimension. The cube I have has the following high-level structure:

geography: region < country
form: super-form < form
vendor: vendor
measures: units

this structure easily lets me view the top X vendors in any combination of geography and form and provides the sum for units, but what I need is a market share value for each vendor for any given combination of region-country and super-form.

Any ideas, help, anyone...

Thanks in advance,

Michael