Word VBA Progress Bar with Unknown Number of Steps - vba

Question

I have a macro that loops through an unknown number of times. The number of times varies based on a total number of rows in multiple tables in a reference document, and that number of rows will vary across reference documents that may be used. The relevant snippet of code for the loop is below:
For Each oRow In oTbl.Rows
p = p + 1
Helper.ProgressIndicator_Code (p)
strPhrase = Split(Trim(oRow.Range.Cells(1).Range.Text), vbCr)(0)
strRule = Split(Trim(oRow.Cells(2).Range.Text), vbCr)(0)
If strPhrase <> "" Then
If Not strStartWord = vbNullString Then
'Process defined sections
arrEndWords = Split(strEndWord, "|")
For lngIndex = 0 To UBound(arrEndWords)
Set oRng = GetDocRange(strStartWord, arrEndWords(lngIndex))
If Not oRng Is Nothing Then Exit For
Next lngIndex
Else
'Process whole document
Set oRng = m_oDocCurrent.Range
End If
If Not oRng Is Nothing Then
Set oRngScope = oRng.Duplicate
With oRng.Find
.Text = strPhrase
Do While .Execute
If Not oRng.InRange(oRngScope) Then Exit For
oRng.HighlightColorIndex = wdTurquoise
If strRule <> "" Then
Set oComment = m_oDocCurrent.Comments.Add(Range:=oRng, Text:=strUsr & ": " & strRule)
oComment.Author = UCase("WordCheck")
oComment.Initial = UCase("WC")
End If
Loop
End With
End If
End If
Next oRow
The progress bar is a classic progress bar for which a label field width is updated using the below code based on a value of p as updated in the above code:
Sub progress(pctCompl As Integer)
ProgressIndicator.Text.Caption = pctCompl & "% Completed"
ProgressIndicator.Bar.Width = pctCompl * 2
DoEvents
End Sub
Here's my problem: The value of p varies based on which reference document is used, so my progress bar is never even approximately accurate with respect to the processing of the VBA macro. The progress bar doesn't have to be exact, merely close and to indicate that progress is being made and nothing has hung.
I'm not looking for written code, just would be very grateful for suggestions or advice as to approaches for making my progress bar more accurate so that I can learn (e.g., I just ran the macro for three different reference documents - one gave me 25%, one gave 44%, and one gave 82%; none showed even close to 100% when completed). Essentially I need to divide i by an unknown number to get my percentage, which is clearly impossible, so some function for a close approximation is needed.
Edit: New code based on #macropod suggestion.
Dim strCheckDoc As String, docRef As Document, projectPath As String, _
j As Integer, i As Integer, k As Integer, oNumRows as Long
j = 1
For i = 0 To UBound(strUsr)
strCheckDoc = [path to reference document unique to each strUsr]
Set docRef = Documents.Open(strCheckDoc, ReadOnly:=True, Visible:=False)
For k = 1 To docRef.Tables.Count
oNumRows = oNumRows + docRef.Tables(i).Rows.Count
Next k
Next i
Then the code to update the progress bar is:
Dim pctCompl As Single
pctCompl = Round((p / oNumRows) * 100)
ProgressIndicator.Text.Caption = pctCompl & "% Completed"
ProgressIndicator.Bar.Width = pctCompl * 2
DoEvents
The progress bar now gets to 64% when complete (i.e., it should be at 100%). I'm also working on a way to make oNumRows only count a row if the row has content in the first column.