You can't add data to a pivot chart that isn't part of the pivot table. And
totals and subtotals don't count.
You can make a regular chart from the pivot data. Start with a cell that's
not part of or touching the pivot table, start the chart wizard, then in
step 2, use the Series tab to define the data. (Using the Data Range tab
will change the chart irreversibly into a pivot chart). Then you can add a
series to display the target:
You might have some success in a pivot chart if you include calculated
fields. Someone emailed me to say it could be done, but there was no
example, and I haven't had time to figure it out from scratch.
