Is there a way to display data like I've shown it below. In case it is
unclear, I'd like to calculate a percentage of sales of size 1 to the total
sales of the various sizes of a product. For example, Prod A, size 1, as a
percentage of total sales of Prod A, sizes 1-3.


Product Size Units %
A 1 100 16.7%
A 2 200 33.3%
A 3 300 50.0%
A Total 600 100.0%

B 1 150 20.0%
B 2 350 46.7%
B 3 250 33.3%
B Total 750 100.0%

Total 1350 100.0%