Calculating excess death by national origin of name from French open mortality data

ExcessDeaths.cs

using CsvHelper;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;

namespace FrenchDeaths
{
    class Program
    {
        static void Main(string[] args)
        {
            Dictionary<string, NamesAndDeath> NamesAndDeaths = new Dictionary<string, NamesAndDeath>();

            // get these files from https://www.data.gouv.fr/fr/datasets/fichier-des-personnes-decedees/
            List<string> Deaths2019Raw = File.ReadAllLines("Assets/deces-2019.txt").ToList();
            List<string> Deaths2020Raw = File.ReadAllLines("Assets/deces-2020.txt").ToList();

            foreach (string Deaths in Deaths2019Raw)
            {
                string Name = Deaths.Split("*").First();
                if (NamesAndDeaths.ContainsKey(Name) == false)
                {
                    NamesAndDeaths.Add(Name, new NamesAndDeath() { FamilyName = Name, Deaths2019 = 0, Deaths2020 = 0, Countries = new List<string>() });
                }
                string country = Deaths.Substring(124, 30).Trim();
                if (country != "")
                {
                    NamesAndDeaths[Name].Countries.Add(country);
                }
                NamesAndDeaths[Name].Deaths2019++;
            }
            foreach (string Deaths in Deaths2020Raw)
            {
                string Name = Deaths.Split("*").First();
                if (NamesAndDeaths.ContainsKey(Name) == false)
                {
                    NamesAndDeaths.Add(Name, new NamesAndDeath() { FamilyName = Name, Deaths2019 = 0, Deaths2020 = 0, Countries = new List<string>() });
                }
                string country = Deaths.Substring(124, 30).Trim();
                if (country != "")
                {
                    NamesAndDeaths[Name].Countries.Add(country);
                }
                NamesAndDeaths[Name].Deaths2020++;
            }
            foreach(NamesAndDeath NAD in NamesAndDeaths.Values)
            {
                NAD.CountriesToWrite = string.Join(", ", NAD.Countries.Distinct());
            }


            List<string> AllCountries = NamesAndDeaths.Values.SelectMany(x => x.Countries).Distinct().ToList();
            List<CountryAndDeath> CountriesAndDeaths = new List<CountryAndDeath>();
            foreach (string Country in AllCountries)
            {
                CountryAndDeath CAD = new CountryAndDeath()
                {
                    Country = Country,
                    Deaths2019 = NamesAndDeaths.Values.Where(x => x.Countries.Contains(Country)).Sum(x => x.Deaths2019),
                    Deaths2020 = NamesAndDeaths.Values.Where(x => x.Countries.Contains(Country)).Sum(x => x.Deaths2020)
                };
                if (CAD.Deaths2019 != 0)
                {
                    CAD.PercentIncreaseIn2020 = (CAD.Deaths2020 - CAD.Deaths2019) / (double)CAD.Deaths2019;
                }
                CountriesAndDeaths.Add(CAD);
            }
            CountryAndDeath CADAll = new CountryAndDeath()
            {
                Country = "All",
                Deaths2019 = NamesAndDeaths.Values.Sum(x => x.Deaths2019),
                Deaths2020 = NamesAndDeaths.Values.Sum(x => x.Deaths2020)
            };
            CADAll.PercentIncreaseIn2020 = (CADAll.Deaths2020 - CADAll.Deaths2019) / (double)CADAll.Deaths2019;
            CountriesAndDeaths.Add(CADAll);



            // this method of writing the CSV is long -- but it create CSVs better suited for opening in Excel and PowerBI
            if (File.Exists(@"FrenchDeaths.csv"))
            {
                File.Delete(@"FrenchDeaths.csv");
            }
            using (StreamWriter _textWriter = new StreamWriter(File.OpenWrite(@"FrenchDeaths.csv"), new UTF8Encoding(true)))
            {
                using (CsvWriter _csvwriter = new CsvWriter(_textWriter, CultureInfo.CurrentCulture))
                {
                    _csvwriter.WriteRecords(NamesAndDeaths.Values.OrderByDescending(x => x.Deaths2020));
                }
            }

            // this method of writing the CSV is long -- but it create CSVs better suited for opening in Excel and PowerBI
            if (File.Exists(@"FrenchDeathsByCountry.csv"))
            {
                File.Delete(@"FrenchDeathsByCountry.csv");
            }
            using (StreamWriter _textWriter = new StreamWriter(File.OpenWrite(@"FrenchByCountry.csv"), new UTF8Encoding(true)))
            {
                using (CsvWriter _csvwriter = new CsvWriter(_textWriter, CultureInfo.CurrentCulture))
                {
                    _csvwriter.WriteRecords(CountriesAndDeaths.OrderByDescending(x => x.PercentIncreaseIn2020));
                }
            }
        }
    }
    class CountryAndDeath
    {
        public string Country { get; set; }
        public int Deaths2019 { get; set; }
        public int Deaths2020 { get; set; }
        public double PercentIncreaseIn2020 { get; set; }
    }
    class NamesAndDeath
    {
        public string FamilyName { get; set; }
        public int Deaths2019 { get; set; }
        public int Deaths2020 { get; set; }
        public List<string> Countries { get; set; }
        public string CountriesToWrite { get; set; }
    }
}