FFO / Net debt can be estimated as:

- **FFO (funds from operations)** ≈ cash flow from operations before working-capital movements, adjusted for interest and taxes paid.  
  From the cash-flow statement, **Cash flows from operations before changes in working capital (2022)** = **€2,072.7m**. This is a suitable FFO proxy because it starts from profit and adds back non-cash items, while excluding working-capital swings.

- **Net debt** ≈ interest-bearing borrowings and financial liabilities minus cash and financial assets.  
  At 2022 year-end:
  - Long-term borrowings = €8,416.7m
  - Short-term borrowings = €444.1m
  - Current portion of long-term borrowings = €1,909.3m
  - Noncurrent financial liabilities = €247.2m
  - Current financial liabilities = €44.9m  
  Gross financial debt/liabilities = **€11,062.2m**

  Less:
  - Cash and cash equivalents = €2,155.1m
  - Current financial assets = €255.3m
  - Noncurrent financial assets = €494.4m  
  Cash and financial assets = **€2,904.8m**

  Estimated net debt = €11,062.2m − €2,904.8m = **€8,157.4m**

Therefore:

FFO / Net debt = €2,072.7m / €8,157.4m = **0.2541**, or about **25.4%**.

<answer>25.4%</answer>