68 580 metric tons 60 960 metric tons 45 720 metric tons 30 480 metric tons 15 240 metric tons
1973, 68 580 tonna méadrach 1974, 60 960 tonna méadrach 1975, 45 720 tonna méadrach 1976, 30 840 tonna méadrach 1977, 15 240 tonna méadrach