Brad,

This might get you part way there. Paste your table, put the cursor in
the heading cell of the short column and run the following macro:

Sub ScratchMacro()
Dim iCount As Long
Dim oCell As Cell
Dim oCol As Column
Dim oTable As Table
Dim X As Long

If Selection.Information(wdWithInTable) = True Then
Set oTable = Selection.Tables(1)
Set oCol = Selection.Columns(1)
Else
MsgBox "Selection is not in a table"
Exit Sub
End If
iCount = -1
X = oTable.Rows.Count - 1
For Each oCell In oCol.Cells
If oCell.Range.Characters.Count 1 Then
iCount = iCount + 1
End If
Next
Selection.InsertBefore "" & (iCount / X) * 100 & " %"
End Sub

If your short column is always column 1 or column 2 then I suppose that
you could refine this macor to perform the same rountine for each table
in activedocument.tables. I haven't figured that out though.