how to calculate datatable size in C#

using System;
using System.Data;

public class DataTableComputeExample
{
    public static void Main()
    {
        //adding up a new datatable
        DataTable dtEmployee = new DataTable("Employee"); 

        //adding up 3 columns to datatable
        dtEmployee.Columns.Add("ID", typeof(int));
        dtEmployee.Columns.Add("Name", typeof(string));
        dtEmployee.Columns.Add("Salary", typeof(double));

        //adding up rows to the datatable
        dtEmployee.Rows.Add(52, "Human1", 21000);
        dtEmployee.Rows.Add(63, "Human2", 22000);
        dtEmployee.Rows.Add(72, "Human3", 23000);
        dtEmployee.Rows.Add(110,"Human4", 24000);

        Console.Write("Employee Count:");
        Console.WriteLine(dtEmployee.Compute("Count(ID)", string.Empty));

        Console.Write("Maximum Salary:");
        Console.WriteLine(dtEmployee.Compute("Max(Salary)",string.Empty));

        Console.Write("Minimum Salary:");
        Console.WriteLine(dtEmployee.Compute("Min(Salary)", string.Empty));

        Console.Write("Average Salary:");
        Console.WriteLine(dtEmployee.Compute("Avg(Salary)", string.Empty));

        Console.Write("Sum Salary:");
        Console.WriteLine(dtEmployee.Compute("Sum(Salary)", string.Empty));

        Console.ReadLine();
    }

}

Output:

Employee Count:4
Maximum Salary:24000
Minimum Salary:21000
Average Salary:22500
Sum Salary:90000