Поиск среднего значения в коллекции List

class Program
    {
        static void Main(string[] args)
        {
            var List = new List<Employee>();
            List.Add(new Employee { Name = "Ирина", Surname = "Жунусова", Salary = 30000, Post = "Дизайнер", Experience = "12" });
            List.Add(new Employee { Name = "Алексей", Surname = "Данилов", Salary = 35000, Post = "3D-дизайнер", Experience = "10" });
            List.Add(new Employee { Name = "Виктор", Surname = "Крюков", Salary = 40000, Post = "Раработчик АО", Experience = "10" });
            List.Add(new Employee { Name = "Денис", Surname = "Борисов", Salary = 35000, Post = "Веб-программист", Experience = "7" });
            List.Add(new Employee { Name = "Вячеслав", Surname = "Юшманов", Salary = 35000, Post = "Разработчик ПО", Experience = "5" });
            List.Add(new Employee { Name = "Игорь", Surname = "Ачмиз", Salary = 25000, Post = "Генератор идей", Experience = "8" });
            List.Add(new Employee { Name = "Михаил", Surname = "Ильченко", Salary = 25000, Post = "Системный администратор", Experience = "3" });
            double inAverageSalary = List.Average(Func<Employee, out int> Salary); 
            
            Console.ReadKey();
        }
 
        public struct Employee
        {
            public string Name { get; set; }
            public string Surname { get; set; }
            public int Salary { get; set; }
            public string Post { get; set; }
            public string Experience { get; set; }
                  
            public override string ToString()
            {
                return Surname + ", зарплата " + Salary + " руб, должность " + Post + ", стаж " + Experience + " лет.";
            }
        } 
    }

double inAverageSalary = List.Average(employee => employee.Salary);

[CompilerGenerated]
private static int <Main>b__7(Employee employee)
{
    return employee.Salary;
}

double inAverageSalary = List.Average((Func<Employee, int>)GetSalary);
 
        static int GetSalary(Employee employee)
        {
            return employee.Salary;
        }