1. Entries onto and removals from the registers shall be updated at least annually.
2. The frequency of updating shall depend on the kind of unit, the variable considered, the size of the unit and the source generally used for the update.
3. The measures relating to the rules for updating, designed to amend non-essential elements of this Regulation by supplementing it, shall be adopted in accordance with the regulatory procedure with scrutiny referred to in Article 16(3).
4. Member States shall make annually a copy that reflects the state of the registers at the end of the year and keep that copy for at least 30 years for the purpose of analysis.