To estimate the FFO / Net debt ratio for 2022, we need to calculate **Funds From Operations (FFO)** and **Net Debt** for that year.

**1. Estimating Funds From Operations (FFO)**
FFO is typically approximated from the cash flow statement. A common approach is:
Cash flows from operating activities – interest paid – interest on lease (or a more direct calculation from EBITDA). 
Given the data, we can use:
*   Cash flows from operating activities (2022): 4,148,200,000 EUR
*   Minus Interest paid (2022): 637,700,000 EUR
*   Minus Interest on lease (2022): 52,500,000 EUR
FFO ≈ 4,148,200,000 - 637,700,000 - 52,500,000 = 3,458,000,000 EUR

Alternatively, if we follow a definition adding back operating depreciation and subtracting some items, let's look at "Cash flows from operations before changes in working capital" (4,804,300,000 EUR). This figure already excludes interest and tax payments.
Another formula: FFO ≈ EBITDA – Current Income Tax – Interest Paid – Interest on Lease.
Operating Income Before Share = 2,206,300,000 EUR
Depreciation = 3,178,600,000 EUR
EBITDA = 2,206,300 + 3,178,600 = 5,384,900,000 EUR
Tax Paid = 557,400,000 EUR
Interest Paid = 637,700,000 EUR
Interest on Lease = 52,500,000 EUR
FFO ≈ 5,384,900,000 - 557,400,000 - 637,700,000 - 52,500,000 = 4,137,300,000 EUR

Let's use the "Cash flows from operations before changes in working capital" as a base, which equals 4,804,300,000 EUR.
This figure already excludes net finance costs. However, it includes dividends received? No, dividends from associates are in investing.
From this, we deduct interest paid (637,700,000 EUR) and interest on lease (52,500,000 EUR).
FFO ≈ 4,804,300,000 - 637,700,000 - 52,500,000 = 4,114,100,000 EUR

Let’s stick with the simpler FFO = Operating Cash Flow - Interest - Lease Interest.
FFO = 4,148,200,000 (Op CF) - 637,700,000 (Int) - 52,500,000 (Lease Int) = **3,458,000,000 EUR**.

**2. Estimating Net Debt**
Net Debt = (Non-current financial liabilities + Current financial liabilities) - (Cash and cash equivalents + Other current financial assets?)
Strict definition: Gross Debt - Cash.
Gross Debt 2023-01-01:
*   Non-current Financial Liabilities Excluding Concession: 19,692,100,000 EUR
*   Non-current Lease Liabilities: 1,656,200,000 EUR
*   Current Financial Liabilities Excluding Concession: 6,521,400,000 EUR
*   Current Lease Liabilities: 496,500,000 EUR
*   Bank Overdrafts: 213,600,000 EUR
Total Gross Debt = 19,692,100,000 + 1,656,200,000 + 6,521,400,000 + 496,500,000 + 213,600,000 = 28,579,800,000 EUR

Cash (2023-01-01):
*   Cash and Cash Equivalents: 9,012,200,000 EUR

Net Debt = 28,579,800,000 - 9,012,200,000 = **19,567,600,000 EUR**.

**3. Ratio**
FFO / Net Debt = 3,458,000,000 / 19,567,600,000 = 0.1767

<answer>0.1767</answer>