Reasoning:

To estimate Net Debt / EBITDA using an S&P-style approach from the available annual-report facts:

1. Estimate gross financial debt  
   Use interest-bearing borrowings:
   - Long-term borrowings: €5,491.124 million
   - Current borrowings and current portion of noncurrent borrowings: €721.845 million

   Gross debt ≈ 5,491.124 + 721.845 = €6,212.969 million

2. Subtract cash and cash equivalents  
   - Cash and cash equivalents: €794.824 million

   Net debt ≈ 6,212.969 - 794.824 = €5,418.145 million

3. Estimate EBITDA  
   EBITDA can be approximated as:
   - Operating profit: €961.554 million
   - Add back depreciation and amortisation: €544.992 million

   EBITDA ≈ 961.554 + 544.992 = €1,506.546 million

4. Calculate Net Debt / EBITDA  
   Net Debt / EBITDA ≈ 5,418.145 / 1,506.546 = 3.596

Rounded to one decimal place, the estimated ratio is about 3.6.

<answer>3.6</answer>