// Create 2 files
        // 1. Series - Books
        // 2. Books - Sales
        public static void AssembleSalesData(string pathDataDir)
        {
            Console.WriteLine("Starting to assemble comics sales data . . .");

            SeriesSalesData seriesSales = new SeriesSalesData();
            string pathSalesData = Path.Combine(pathDataDir, FileManager.DEFAULT_SALES_DIR);

            foreach (string pathSalesFile in Directory.EnumerateFiles(pathSalesData, "*", SearchOption.TopDirectoryOnly))
            {
                Console.WriteLine(String.Format("Processing data from {0}.", pathSalesFile));
                FileManager.ReadSalesDataFromCSV(pathSalesFile, ref seriesSales);
            }

            Console.WriteLine("Saving assembled data . . .");

            string pathResultsDir = Path.Combine(pathDataDir, FileManager.DEFAULT_RESULTS_DIR);
            FileManager.WriteToCSV(seriesSales, Path.Combine(pathResultsDir, FileManager.RESULT_SERIES_COMICS_SALES), true);
            FileManager.WriteToCSV(seriesSales, Path.Combine(pathResultsDir, FileManager.RESULT_COMICS_SALES), false);

            Console.WriteLine(String.Format("---=== Statistics ===---\n# Series: {0}",
                              seriesSales.Count()));

            Console.WriteLine("Finished comics sales data assembling.");
        }