I don't think I'd use Get (foundcount) for this, I'd use a summary "count of" field instead.
Create your summary report so that it previews/prints with the data in the manner you need for your graph.
Choose export records and select and excel file format.
Use the "group by" window to specify the same field your grouped your summary report. Specify the data fields you want and this should give you the excel file you want.