OPINION OF THE ECONOMIC AND SOCIAL COMMITTEE ON THE PROPOSAL FOR A COUNCIL REGULATION AMENDING REGULATION NO 136/66/EEC AND REGULATIONS ( EEC ) NO 804/68, ( EEC ) NO 805/68, ( EEC ) NO 727/70, ( EEC ) NO 1035/72, ( EEC ) NO 2727/75, ( EEC ) NO 2759/75, ( EEC ) NO 2771/75, ( EEC ) NO 2777/75, ( EEC ) NO 1418/76, ( EEC ) NO 516/77, ( EEC ) NO 337/79 AND ( EEC ) NO 1837/80 WITH REGARD TO THE FIXING OF EXPORT REFUNDS FOR CERTAIN AGRICULTURAL PRODUCTS BY TENDERING PROCEDURE