The compilation of statistics on labour costs shall be based on any of the statistical units defined in Council Regulation (EEC) No 696/93 of 15 March 1993 on the statistical units for the observation and analysis of the production system in the Community6 and shall provide information referring to local units classified by their own principal activity, by region at least at level 1 of the nomenclature of territorial units for statistics (NUTS 1), established by the Commission and by size class in terms of employment of the enterprise on which the local units are dependent. Information is required only for enterprises with at least 10 persons occupied.