The prices taken for the purposes of calculating the producer prices referred to in Article 75 (2) (a) of the Act of Accession shall be those recorded for a home-grown product, defined as to commercial characteristics, on the representative market or markets located in the production areas in which the prices are lowest, for products or varieties representing a large proportion of production marketed throughout or during part of the year and which correspond to quality Class
I and meet specific conditions with regard to packaging.