How to set the width of the chart series in asp .net 3.5 using dataVisualization

<asp:Chart ID="Chart1" runat="server"
           Palette="Chocolate">
           <Series>
               <asp:Series Name="Series1" Color="Bisque" LegendText="Test" MarkerSize="1"
                   MarkerStyle="Triangle" XValueMember="RegNo" XValueType="String"
                   YValueMembers="Trips" YValueType="Int32">
               </asp:Series>
           </Series>
           <ChartAreas>
               <asp:ChartArea Name="ChartArea1">
              <AxisX Title="Vehicle"></AxisX>
              <AxisY Title="Trips"></AxisY>
                   <InnerPlotPosition Height="70" Width="70" X="9.7804" Y="3.35106" />
                   <Area3DStyle Enable3D="True" Rotation="0" WallWidth="0" />
               </asp:ChartArea>
           </ChartAreas>
       </asp:Chart>

private void BindChart()
   {
       DataTable dt = getData();
       int i = 0;
       foreach (DataRow dr in dt.Rows)
       {
           if (i < 5)
           {
               Chart1.Series[0].Points.AddXY(dr["RegNo"].ToString(), dr["Trips"].ToString());
               Chart1.Series[0].Points[i].ToolTip = dr["RegNo"].ToString() + " - " + dr["Trips"].ToString();
               Chart1.Series[0].Points[i].Label = dr["Trips"].ToString();
           }
           i++;
       }
       Chart1.Width = Unit.Pixel(dt.Rows.Count * 20);
   }

   public DataTable getData()
   {
       SqlConnection con = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["TransportConnectionString"].ConnectionString);
       SqlCommand cmd = new SqlCommand("Select COUNT(TripID) as Trips,RegNo from TRNS.Trip Group By RegNo", con);
       DataTable dt = new DataTable();
       con.Open();
       dt.Load(cmd.ExecuteReader());
       con.Close();
       return dt;
   }