Sale of residential investment property

I have sold a residential investment property.  Over the years that I owned the property, I made significant improvements.  These improvements appear on the depreciation/asset list along with the actual structure.  If I understand correctly from another posting in the TT Community, I must allocate the sale price to each item on the asset list, and the land as well.  Does that mean applying a portion of the sale proceeds to each item?  If so, how do I determine how much of the sale proceeds went towards that item?  Such as a new roof? or the new siding? or the new countertop? etc. etc. etc.  

All items on the asset list were included in the sale, and the sale proceeds went to all items on the asset list.  In other words, it was a "package deal".  Thanks for your help.