how generate random number of row

for(int i=0; i<20; i++)
{
    string sqlQuery = "INSERT INTO table(blah)";
    sqlQuery += "VALUES (@blah)";
    using (SqlConnection dataConnection = new SqlConnection(connectionString))
    {
        using (SqlCommand dataCommand = dataConnection.CreateCommand())
            {
            dataConnection.Open();
            dataCommand.CommandType = CommandType.Text;
            dataCommand.CommandText = sqlQuery;
            dataCommand.Parameters.Add("@blah", text to insert);
            dataCommand.ExecuteNonQuery();
            dataConnection.Close();
            }
    }
}