To determine the extent to which the company should utilize hybrid bonds relative to the 15% equity credit cap, we must analyze the company’s capital structure and interest rate environment.

1.  **Capital Structure Analysis (2022 Data):**
    *   **Equity:** 58,114,000,000 EUR
    *   **Non-current Financial Liabilities:** 44,216,000,000 EUR
    *   **Current Financial Liabilities:** 25,079,000,000 EUR
    *   **Total Debt:** ~69,295,000,000 EUR
    *   **Total Adjusted Capital (Debt + Equity):** 127,409,000,000 EUR
    *   **15% Cap:** 0.15 * 127,409,000,000 = 19,111,350,000 EUR.

2.  **Market Context (2022):**
    *   The swap curves (5Y, 7Y, 10Y) significantly increased in 2022 compared to 2021 (e.g., 10Y swap went from 0.053% to 1.927%).
    *   The iBoxx EUR Non-Financial IG spreads also widened (average 2.295% in 2022 vs 1.298% in 2021).
    *   Rising interest rates make issuing pure debt more expensive. Hybrids offer a way to manage leverage while receiving partial equity credit, which supports the credit rating.

3.  **Strategy:**
    *   Iberdrola maintains a high level of capital expenditure (Property, Plant, and Equipment increased significantly).
    *   Given the significant rise in interest rates and borrowing costs in 2022, maximizing the use of hybrids—up to the regulatory limit—is a common strategy for large utility companies to optimize their cost of capital while preserving their credit rating.
    *   Given the gap between current hybrid usage (subordinated perpetual obligations are relatively small compared to the 19 billion EUR capacity) and the S&P cap, the company has significant room to utilize these instruments to shift the capital structure efficiently. Aligning with an aggressive approach to interest rate management and balance sheet optimization suggests utilizing the full capacity allowed by the rating agency.

<answer>100%</answer>