The following rewrite should get you what you are looking for:
Const MAX_CONTROLS As Integer = 10
' Clear the existing controls
For i = 0 To MAX_CONTROLS - 1
Controls.Item("LblStckRnk" & i).Text = ""
Next
Dim queryString As String
queryString = "SELECT EMPLOYEE_NAME AS EMPLOYEE, AVG(EFFICIENCY_YIELD) AS YIELD FROM dbo.APE_BUSDRIVER_MAIN WHERE YEAR_TIME = " & cbYear.Text & " AND APE_AREA_OBJID = " & lblAreaOBJID.Text & " AND ACTIVE = 1 GROUP BY EMPLOYEE_NAME ORDER BY YIELD " & lblSortOrder.Text & ""
Using connection As New SqlConnection(SQLConnectionStr)
Using command As New SqlCommand(queryString, connection)
connection.Open()
Using reader As SqlDataReader = command.ExecuteReader()
Dim i As Integer = 0
While reader.Read() AndAlso i < MAX_CONTROLS
Controls.Item("LblStckRnk" & i).Text = reader("EMPLOYEE")
i += 1
End While
reader.Close()
End Using
End Using
End Using