For salary expenses in the fiscal year, do I use the budgeted amount, or actual expenditures?

Use actual expenditures.  That way you will have a record of what really happened.  Labor is a vital determinate to the level of services a library can offer.  A budget is only a potential.  Actual expenditures would reflect freezes and vacancies, which would be echoed by the level of such measures as open hours, reference, programming, etc.