how to show count of the column on the crystal report in vb.net

RptSurname.Show()
       Dim qry As String = "SELECT Count([LastName]) AS surname,lastname  FROM Voter group by (lastname)"
       Dim da As New OleDbDataAdapter(qry, My.Settings.trialConnectionString)
       Dim ds As New trialDataSet
       da.Fill(ds, "voter")
       Dim rpt As New RptSurane
       rpt.SetDataSource(ds)
       RptSurname.CrystalReportViewer1.ReportSource = rpt

count of lastname   lastname

      10             Kumbhar

      21             Patil