LiteDB Test of 16000 records

Program.cs

using System;
using LiteDB;
using System.Collections.Generic;
using System.Text;
namespace LiteDBTesting
{
    class Company
    {
        public int Id { get; set; }
        public string CompanyName { get; set; }
        public string AddressLine1 { get; set; }
        public string AddressLine2 { get; set; }
        public string PostalCode { get; set; }
        public DateTime Created { get; set; }

        public List<Invoice> Invoices { get; set; }

        public Company()
        {
            Invoices = new List<Invoice>();
        }

        public override string ToString()
        {
            StringBuilder sb = new StringBuilder();
            sb.AppendLine(this.CompanyName);
            sb.AppendLine(this.AddressLine1);
            sb.AppendLine(this.AddressLine2);
            sb.AppendLine(this.PostalCode);
            return sb.ToString();
        }
    }

    class Invoice
    {
        public DateTime InvoiceDate { get; set; }
        public List<string> Lines { get; set; }
        public double Total { get; set; }

        public Invoice()
        {
            Lines = new List<string>();
        }
    }

    class Stat
    {
        public int Id { get; set; }
        public DateTime Timestamp { get; set; }
        public int Count { get; set; }
    }

    class Program
    {
        static void Main(string[] args)
        {
            double insertTime = Insert();
            int count;
            
            using (var db = new LiteDatabase(@"MyData.db"))
            {
                var companies_db = db.GetCollection<Company>("company");

                count = companies_db.Count();
            }
            Console.WriteLine("Inserted {0} records in {1} seconds.", count, insertTime);
            Console.ReadKey();
        }
        static double Insert()
        { 
            int NumOfCompanies = 16000;
            int NumOfInvoices = 10;
            using (var db = new LiteDatabase(@"MyData.db"))
            {
                Console.WriteLine("Hello World!");

                var companies_db = db.GetCollection<Company>("company");
                var stats_db = db.GetCollection<Stat>("Statistics");
                companies_db.EnsureIndex(i => i.CompanyName, true);
                DateTime timer = new DateTime();
                //companies_db.EnsureIndex(i => i.Invoices., true);
                Stat stat = new Stat() { Timestamp = DateTime.Now, Count = 0 };
                stats_db.Insert(stat);
                DateTime start = DateTime.Now;
                timer = DateTime.Now;
                TimeSpan onesecond = new TimeSpan(0, 0, 1);
                for (int i = 1; i <= NumOfCompanies; i++)
                {
                    if (DateTime.Now - timer > onesecond)
                    {
                        stat = new Stat() { Timestamp = DateTime.Now, Count = i - stat.Count };
                        stats_db.Insert(stat);
                        timer = DateTime.Now;
                        //Console.Clear();
                        //Console.WriteLine(i);
                    }
                    Company c = new Company()
                    {
                        Id = i,
                        CompanyName = "SmithAndCo-" + i,
                        AddressLine1 = "138" + i + "Ave.",
                        AddressLine2 = "Kelowna BC",
                        PostalCode = "1A2-3B4",
                        Created = DateTime.Now
                    };

                    for(int j = 0; j < NumOfInvoices; j++)
                    {
                        Invoice inv = new Invoice() { InvoiceDate = DateTime.Now.AddDays(i) };
                        inv.Lines.Add("Line 1");
                        inv.Lines.Add("Line 2");
                        inv.Total = 100 + ((NumOfCompanies % 3) * NumOfInvoices);
                        c.Invoices.Add(inv);
                    }

                    companies_db.Insert(c);
                }

                DateTime finished = DateTime.Now;
                return (finished - start).TotalSeconds;
            }
        }


    }
}