Nevermind,

Again, assuming column A with data starting in row 2:

[vba]With ActiveSheet
.Range("B10").Formula = _
"=IF(SUMPRODUCT(--(YEAR(A2:A" & .Cells(.Rows.Count, 1).End(xlUp).Row & _
")=YEAR(A2)))=COUNT(A2:A" & .Cells(.Rows.Count, 1).End(xlUp).Row & "),""Yes"",""No"")"
End With[/vba]