To estimate S&P's adjusted leverage trend, we need to calculate the Net Debt / EBITDA ratio for both 2022 and 2021, as the period 2022-01-01 to 2023-01-01 represents the 2022 fiscal year, and 2021-01-01 to 2022-01-01 represents the 2021 fiscal year. 

1. **Calculate EBITDA for each year:**
EBITDA is typically calculated as Operating Profit (EBIT) + Depreciation and Amortization (D&A).
- For 2022: 
  - Operating Profit = €565,851,000
  - D&A (Adjustments For Depreciation And Amortisation Expense) = €594,636,000
  - EBITDA 2022 = 565,851,000 + 594,636,000 = €1,160,487,000
- For 2021: 
  - Operating Profit = €581,101,000
  - D&A = €546,626,000
  - EBITDA 2021 = 581,101,000 + 546,626,000 = €1,127,727,000

2. **Calculate Net Debt for each year:**
Net Debt = Total Financial Debt - Cash and Cash Equivalents. Total Financial Debt is the sum of Noncurrent and Current Financial Liabilities.
- For 2022 (end of year, 2023-01-01):
  - Noncurrent Financial Liabilities = €4,722,263,000
  - Current Financial Liabilities = €619,418,000
  - Total Financial Debt 2022 = 4,722,263,000 + 619,418,000 = €5,341,681,000
  - Cash = €559,908,000
  - Net Debt 2022 = 5,341,681,000 - 559,908,000 = €4,781,773,000
- For 2021 (end of year, 2022-01-01):
  - Noncurrent Financial Liabilities = €4,791,979,000
  - Current Financial Liabilities = €285,222,000
  - Total Financial Debt 2021 = 4,791,979,000 + 285,222,000 = €5,077,201,000
  - Cash = €680,820,000
  - Net Debt 2021 = 5,077,201,000 - 680,820,000 = €4,396,381,000

3. **Calculate Net Debt / EBITDA ratio for each year:**
- Ratio 2022 = 4,781,773,000 / 1,160,487,000 ≈ 4.12x
- Ratio 2021 = 4,396,381,000 / 1,127,727,000 ≈ 3.90x

4. **Determine the trend:**
- Gap (Year-over-Year Change) = 4.12x - 3.90x = +0.22x
- According to the criteria, Stable is a gap between ±0.3x. If the gap is lower than 0.3x (meaning strictly less than 0.3x), it is Improving. If higher, it is Deteriorating. 
- Because 0.22x is lower than 0.3x, the trend is Improving.

<answer>Improving</answer>