public AnnualBudgetReport(IMoneyCalculator calculator, IEnumerable <MonthlyBudgetReport> months)
        {
            Months = months.ToList();

            Income  = FinancialStats.GetTotal(calculator, Months.Select(n => n.Income));
            Expense = FinancialStats.GetTotal(calculator, Months.Select(n => n.Expense));

            Balance = FinancialStats.GetBalance(calculator, Income, Expense);
        }