Algo Modulus File of Dates per-day to Chart.linq

<Query Kind="Program" />

void Main()
{
	
	//var dates = System.IO.File.ReadAllLines(@"c:\dates.txt").Select(d => DateTime.Parse(d).Date);
	var dates = ExampleData().Select(d => DateTime.Parse(d).Date);
	
	var epoch = dates.Min();
	var groupingCount = 1;
	
	var baseGroup = Enumerable.Range(0,(dates.Max()-epoch).Days+groupingCount)
						.Select(e => epoch.AddDays(e) )
						.GroupBy(d => d.AddDays(-(d - epoch).Days % groupingCount))
						.OrderBy(o => o.Key);
	var dateGroup = dates.GroupBy(d => d.AddDays(-(d - epoch).Days % groupingCount))
						.OrderBy(o => o.Key);
	
	var reportResult = (from baseItm in baseGroup
	 join date in dateGroup on baseItm.Key equals date.Key into joinSet
	 from result in joinSet.DefaultIfEmpty()
	 select new { range = baseItm.Key, count= result?.Count()??0}
	);

	reportResult.Dump();
	reportResult.Chart(r => r.range.ToString("d"), v => v.count).Dump();
	reportResult.Average(r => r.count ).Dump("Count per Day");

}

// Define other methods and classes here
private List<string> ExampleData ()
{
	return
	@"08/06/2019
09/13/2019
03/20/2019
09/08/2019
01/16/2019
01/12/2019
02/27/2020
06/22/2020
09/27/2019
06/15/2019
07/27/2019
04/22/2020
07/11/2020
03/17/2019
02/20/2019
05/03/2019
05/19/2020
12/16/2019
04/15/2019
06/13/2020
03/15/2020
02/24/2019
05/04/2020
01/24/2019
07/26/2020
02/22/2019
04/04/2020
03/19/2019
03/28/2019
03/19/2019
10/06/2019
03/12/2020
11/10/2019
11/29/2019
05/12/2020
05/14/2020
05/20/2019
04/25/2020
05/10/2020
04/09/2019
09/29/2019
09/12/2019
04/06/2020
02/10/2020
02/05/2019
03/06/2020
06/06/2020
08/03/2019
02/23/2019
11/27/2019
06/15/2020
10/10/2019
08/28/2019
06/27/2020
03/19/2020
09/16/2019
06/14/2020
04/08/2020
09/24/2019
08/22/2019
07/27/2020
02/19/2019
07/30/2019
07/13/2019
07/20/2019
03/23/2020
01/21/2019
02/13/2019
09/13/2019
01/07/2020
03/30/2020
04/09/2020
11/09/2019
06/22/2020
05/22/2020
06/29/2020
02/27/2019
01/11/2020
04/02/2019
11/24/2019
04/24/2019
05/31/2019
06/08/2019
07/26/2019
08/09/2019
03/02/2020
11/06/2019
02/04/2020
04/11/2019
08/04/2019
03/14/2019
05/16/2019
08/25/2019
02/09/2019
05/12/2019
06/13/2020
05/09/2020
02/04/2020
01/20/2019
08/17/2019
10/25/2019
06/08/2020
07/05/2020
06/21/2019
01/19/2019
07/29/2019
04/22/2019
12/29/2019
05/09/2020
04/07/2019
09/23/2019
07/10/2019
01/04/2020
08/19/2019
04/24/2019
03/20/2020
09/29/2019
05/02/2020
03/04/2019
11/22/2019
01/08/2019
12/18/2019
03/26/2020
06/02/2019
09/02/2019
03/28/2019
08/05/2019
01/31/2019
04/25/2019
04/02/2020
11/12/2019
06/08/2020
08/10/2019
07/22/2020
05/25/2020
07/04/2019
03/27/2020
05/06/2019
03/18/2019
03/05/2020
02/27/2019
01/04/2019
03/21/2019
11/25/2019
12/12/2019
10/10/2019
03/17/2019
07/19/2019
03/03/2020
07/21/2020
12/13/2019
07/17/2019
12/08/2019
10/25/2019
03/17/2020
02/05/2019
01/03/2020
12/01/2019
06/05/2020
08/28/2019
02/10/2020
02/14/2019
01/18/2019
03/25/2020
04/06/2019
06/29/2019
04/20/2019
09/14/2019
01/09/2020
02/02/2020
04/07/2020
06/13/2020
12/07/2019
04/26/2020
02/07/2020
04/28/2020
12/16/2019
05/13/2020
06/02/2020
03/07/2020
01/06/2020
07/28/2020
01/12/2020
06/09/2020
02/13/2020
01/03/2019
04/13/2020
03/23/2019
05/02/2019
07/13/2019
10/14/2019
11/22/2019
08/27/2019
08/30/2019
05/20/2020
09/29/2019
08/03/2019
06/15/2020
01/07/2020
05/11/2020
02/15/2019
05/17/2019
09/27/2019
02/02/2020
03/05/2019
10/09/2019
09/23/2019
04/09/2020
07/05/2020
11/20/2019
10/15/2019
02/04/2020
09/11/2019
03/27/2020
05/24/2019
07/23/2020
01/07/2019
08/03/2019
05/20/2019
02/22/2019
01/01/2020
04/21/2019
03/08/2020
01/16/2020
07/24/2019
02/15/2019
07/28/2020
05/06/2020
11/13/2019
08/20/2019
02/20/2020
01/27/2019
02/28/2019
02/27/2019
06/27/2020
01/22/2020
07/27/2019
05/28/2020
03/18/2019
03/16/2020
11/27/2019
01/21/2020
05/18/2019
12/16/2019
10/14/2019
04/05/2019
07/22/2019
03/27/2019
06/26/2020
04/03/2020
02/04/2020
07/05/2020
01/14/2019
11/07/2019
07/25/2020
07/01/2020
05/24/2020
11/16/2019
07/11/2020
06/10/2019
05/17/2019
12/03/2019
02/16/2019
05/25/2020
03/26/2020
01/05/2020
12/22/2019
02/22/2019
07/31/2020
01/13/2019
01/10/2020
06/15/2020
02/01/2020
03/24/2019
09/15/2019
11/20/2019
02/02/2020
12/07/2019
12/04/2019
06/21/2020
01/07/2019
02/03/2019
01/08/2020
02/09/2020
12/07/2019
05/16/2020
03/23/2019
03/17/2019
01/13/2019
02/04/2020
10/05/2019
07/21/2019
03/19/2019
07/03/2020
12/11/2019
07/22/2019
02/19/2019
03/19/2020
08/31/2019
05/09/2019
04/15/2020
03/19/2020
01/21/2019
12/21/2019
01/03/2019
06/30/2020
02/19/2020
01/10/2019
08/01/2019
08/20/2019
12/01/2019
10/27/2019
06/22/2020
07/27/2019
01/12/2020
04/03/2019
11/09/2019
11/26/2019
07/29/2019
03/24/2020
02/24/2020
02/28/2020
03/19/2020
07/23/2019
02/01/2020
12/08/2019
09/22/2019
08/17/2019
11/20/2019
04/18/2019
01/09/2019
08/19/2019
01/16/2019
03/17/2020
03/25/2019
01/04/2019
08/17/2019
04/30/2019
02/09/2019
05/15/2020
02/01/2020
08/17/2019
06/05/2020
11/28/2019
05/25/2020
08/09/2019
03/23/2019
09/09/2019
10/09/2019
09/03/2019
07/24/2019
11/27/2019
01/26/2020
01/20/2019
02/11/2020
05/14/2019
01/29/2020
06/08/2020
09/05/2019
12/16/2019
08/29/2019
01/04/2020
05/01/2019
06/17/2019
03/03/2020
05/26/2019
08/01/2019
04/01/2019
04/23/2019
05/24/2020
05/09/2020
06/27/2020
07/27/2019
02/15/2019
07/22/2019
03/19/2019
10/06/2019
05/02/2020
08/06/2019
12/22/2019
04/14/2019
05/20/2019
05/05/2020
02/19/2020
06/27/2020
08/19/2019
01/21/2020
10/08/2019
01/23/2020
03/13/2019
05/24/2020
02/16/2019
12/19/2019
03/29/2019
06/11/2019
05/16/2019
02/22/2020
03/11/2019
06/22/2020
04/27/2020
04/26/2020
03/28/2020
03/25/2020
01/09/2020
09/21/2019
05/18/2020
02/05/2019
05/11/2019
02/06/2020
05/21/2020
02/26/2019
02/11/2019
04/17/2019
02/22/2020
04/12/2020
03/09/2019
08/24/2019
08/03/2019
07/17/2019
09/24/2019
07/07/2020
05/23/2020
04/29/2020
07/31/2020
03/21/2020
07/07/2020
03/05/2020
11/21/2019
01/14/2020
01/05/2019
11/14/2019
05/25/2020
11/22/2019
01/16/2020
02/23/2019
05/20/2019
06/06/2020
05/17/2020
06/22/2020
04/14/2019
02/11/2020
07/16/2020
04/17/2020
03/04/2019
06/13/2019
05/26/2019
06/16/2020
02/12/2019
06/10/2020
11/20/2019
07/02/2020
10/25/2019
12/11/2019
03/28/2019
02/08/2019
11/04/2019
03/28/2019
03/19/2020
03/14/2020
07/07/2019
12/17/2019
06/04/2020
09/18/2019
03/10/2020
06/02/2020
07/19/2019
11/28/2019
07/27/2020
07/27/2019
05/24/2020
05/13/2020
06/14/2019
06/02/2019
03/12/2019
05/17/2019
08/15/2019
07/16/2020
03/07/2019
07/27/2020
04/14/2019
03/24/2020
06/15/2020
05/03/2019
05/25/2019
04/19/2019
06/30/2020
05/17/2019
01/07/2019
12/19/2019
10/08/2019
06/21/2020
10/30/2019
02/10/2020
07/31/2020
11/02/2019
07/07/2020
07/03/2019
03/19/2020
12/12/2019
02/04/2020".Split('\n').ToList();
}