Something like this will tell you how many are resolved.
Code:
Sub CountComments()
Dim iResolved As Integer, aCmt As Comment
For Each aCmt In ActiveDocument.Comments
If aCmt.Done Then iResolved = iResolved + 1
Next aCmt
MsgBox "Document has " & ActiveDocument.Comments.Count & " comments. " & vbCr & "Resolved: " & iResolved
End Sub