Sub dupliquer()
Dim der&, ref, n&, i&
Application.ScreenUpdating = False
With ActiveSheet
If .FilterMode Then .ShowAllData
der = .Cells(Rows.Count, "a").End(xlUp).Row
For i = der To 1 Step -1
If .Cells(i, "a") = ref Then
n = n + 1
Else
If n > 1 Then
.Rows(i + 1).Insert
.Rows(i + 2).Copy Rows(i + 1)
End If
ref = .Cells(i, "a")...