Need help on construction costs to replace three-story apartment buildings;

[Mark Todd]

I am in Florida, but I'll take any advice anyone might have.  We have three-story buildings at my complex.  The buildings house either ten or 20 units, with no garages, but have decks.   I need to put an accurate replacement cost on the buildings for insurance purposes.  Does anyone happen to know an approximate cost new construction costs per square foot or per unit?  thank you for any help you can provide.