Business & farm

It was rented continuously (at 100%) since that 02/01/2008 date.   By previous depreciation, I just relied on the previous years depreciation schedule.  Would I have to go through each tax return since 2008 to determine the 'previous depreciation'?  An online depreciation calculator I found doesn't rely on 'previous depreciation' like TurboTax is asking.  It just wants the cost basis ($52,650), recovery period (27.5 yrs) and the starting month/year of rental service (02/2008).   Thank you.  Perhaps I should switch to the Desktop version so I can see the schedules/tables.