Is there a report I can pull that will show what the ATS was on a fund for a particular year?

If you use the spending policy process you might be able to get a report that will show you what last year's approved spending amount was.

If you either calculated the spending in FIMS or imported the values into the spending policy "module", then the values are stored in the cash requirement field in the fund summary record for each fund for each year. You can run the View > Spending Policy > Cash Requirement Report to report on the values for the chosen year.

If you imported the values, they should be in the above report, but should also be in the spreadsheet you used for the import.

Depending upon the timing of your calculation and subsequent journal entries, the beginning balance for the year might also hold the spending amount.  If that is the case, you can also run a Trial Balance for period 0 for the applicable year. (Reports > General Ledger > Trial balance - select period 0 on the front screen and the appropriate GL account that represents the fund balance.  You could also run the Reports > General Ledger > Fund balance report for period 0 and pull the value from the appropriate fund balance column.

There are various other options depending upon how your particular organization manages the process.