Sub Demo()
Application.ScreenUpdating = False
Dim bRevShow As Boolean, RevView As Long
Dim r As Long, i As Long, d As Long, o As Long
With ActiveDocument
  With ActiveWindow.View
    bRevShow = .ShowRevisionsAndComments
    RevView = .RevisionsView
    .ShowRevisionsAndComments = False
    .RevisionsView = wdRevisionsViewOriginal
  End With
  o = .ComputeStatistics(wdStatisticCharactersWithSpaces)
  For r = 1 To .Revisions.Count
    With .Revisions(r)
      If .Type = wdRevisionInsert Then i = i + .Range.ComputeStatistics(wdStatisticCharactersWithSpaces)
      If .Type = wdRevisionDelete Then d = d + .Range.ComputeStatistics(wdStatisticCharactersWithSpaces)
    End With
  Next
  With ActiveWindow.View
    .ShowRevisionsAndComments = bRevShow
    .RevisionsView = RevView
  End With
  MsgBox "The active docuument originally contained " & o & " characters." & vbCr & _
  "It has had " & i & " characters added and " & d & " characters deleted." & vbCr & _
  "Additions and deletions account for " & Format(i * 100 / o, "0") & "% and " & Format(d * 100 / o, "0") & "%," & vbCr & _
  "respectively, of the original length."
End With
Application.ScreenUpdating = True
End Sub