Option Explicit
Private Sub ComboBox1_MouseDown(ByVal Button As Integer, ByVal Shift As Integer, ByVal X As Single, ByVal Y As Single)
Dim F As Worksheet, d As Object, dl As Long, Tb, i As Long
Set d = CreateObject("Scripting.Dictionary")
Set F = Worksheets("bd")
dl = F.Range("A" & Rows.Count).End(xlUp).Row
Tb = F.Range("A2:A" & dl).Value2
For i = LBound(Tb) To UBound(Tb)
If Not d.exists(Year(Tb(i, 1))) Then d(Year(Tb(i, 1))) = ""
Next i
Me.ComboBox1.List = d.Keys
End Sub