you must create a summary table. But that i not hard:
You data is in a table (on the left) shrewdly title "Data" and is summarized in a table (on the right) in a table called "Summary". For the table "Summary":
1) make the first row and first column a header
2) B2=SUMIF(Data :: A, "="&A2, Data :: B)
3) select B2 and fill down as needed (select B2 and click, and hold, on the little circle at the bottom right of the selected cell, then drag down)
4) enter then names of the categories in the column A
5) now select the cells in the column B which contain the summary counts then select the pie chart from the charts menu like :
Fantastic, thanks very much, Wayne!
I tried using the technique I found here: https://discussions.apple.com/message/12618627#12618627. But I ran up against the limit of five footer rows. After I used your technique, I ended up re-slicing my data so that I don't actually need more than five rows, but I think this approach is much better for my purposes, as I may need the flexibility later.