reporting services - SSRS percentage of a total

Question

I would like to be able to get the percentage of each row with relation of the whole total. Here is my formula:

=COUNTDISTINCT(Fields!ID.Value, "NameOfRowGrouping") / COUNTDISTINCT(Fields!ID.Value, "TopLevelGroupName")

The percentage it comes out is the percentage between row total and total of each group:

Group       Qty     %
---------------------
Group 1
MemberA       3   40%
MemberB       4   60%

Total         7

Group 2 
MemberC       2   50%
MemberD       2   50%

Total         4

Grand Total  11

I need to know the percentage with relation of the total for all groupings, like so:

Group       Qty     %
---------------------
Group 1
MemberA       3   30%
MemberB       4   40%

Total         7

Group 2 
MemberC       2   15%
MemberD       2   15%

Total         4

Grand Total  11  100%

Answer 1

It sounds like what you want to do is calculate based on the dataset, not the table grouping:

=CountDistinct(Fields!ID.Value)/CountDistinct(Fields!ID.Value, "MyDatasetName")