Non-profit percent expenses report?

I am brand new to Manager, trying to figure out if I can use it for a non-profit.
One of the desired metrics for a non-profit is percentages of expenses used for program activities, administration, and fundraising.
First, I’m not sure the best way to track that in Manager.
Would I use Program, Administration, and Fundraising at the top level of Expenses, and put everything else underneath, or is there a separate way to track that?
Second, the reports seem to all produce just raw numbers, no percentages.
I looked at the Custom report generator, and did not see anything about using percentages instead of raw numbers.
Can anyone suggest a way to track and report this in Manager?

You can export your report to Excel, or another spreadsheet, and calculate % values there