L’inchiesta sul posto ha verificato se i 4 mesi erano rappresentativi per l’intero periodo di 12 mesi confrontando costi e prezzi dei 4 mesi considerati con quelli dei rimanenti 8 mesi. ###>The investigation on spot ensured that the 4 months were representative of the full 12-month period. This was achieved by comparing costs and prices of the 4 months data with the remaining 8 months.