1. The required solvency margin shall be determined on the basis either of the annual amount of premiums or contributions, or of the average burden of claims for the past three financial years.
However, in the case of reinsurance undertakings which essentially underwrite only one or more of the risks of credit, storm, hail or frost, the last seven financial years shall be taken as the reference period for the average burden of claims.
2. Subject to Article 40, the amount of the required solvency margin shall be equal to the higher of the two results as set out in paragraphs 3 and 4 of this Article.
3. The premium basis shall be calculated using the higher of gross written premiums or contributions as calculated below, and gross earned premiums or contributions.
Premiums or contributions in respect of the classes 11, 12 and 13 listed in point A of the Annex to Directive 73/239/EEC shall be increased by 50 %.
Premiums or contributions in respect of classes other than classes 11, 12