Unit values shall be established on the basis of the following elements, which are to be supplied to the Commission by Member States, in relation to each classification heading: (a) the average free-at-frontier unit price, not cleared through customs, expressed in the currency of the Member State in question per 100 kg net and calculated on the basis of prices for undamaged goods in the marketing centres referred to in Annex 27 during the reference period referred to in Article 174 (1) ...
