Reasoning:

FFO / Net debt is typically estimated as:

FFO / Net debt = Funds from operations / Net debt

A practical credit-style estimate of FFO can be derived from operating cash flow before working-capital movements, often approximated as:

FFO ≈ Cash flows from operations excluding working capital

From the provided 2022 data:

- Cash flows from/used in operations excluding EEG working capital: EUR 596 million  
- Net debt = borrowings + lease liabilities − cash and cash equivalents

Debt components at 2023-01-01, representing year-end 2022:

- Long-term borrowings: EUR 19,006 million
- Short-term borrowings: EUR 709 million
- Non-current lease liabilities: EUR 574 million
- Current lease liabilities: EUR 155 million
- Cash and cash equivalents: EUR 6,547 million

So:

Gross debt = 19,006 + 709 + 574 + 155 = EUR 20,444 million

Net debt = 20,444 − 6,547 = EUR 13,897 million

Then:

FFO / Net debt = 596 / 13,897 = 0.0429

As a percentage:

0.0429 × 100 = 4.3%

<answer>4.3%</answer>