gaYEARN QUANTITYN 1950 254413 1951 161370 1952 165674 1953 189956 1954 525645 1955 303596 1956 536273 1957 1108268 1958 572889 1959 516762 1960 496455 1961 458666 1962 504180 1963 1180530 1964 777000 1965 407000 1966 601000 1967 726000 1968 368000 1969 391000 1970 208000 1971 263000 1972 403000 1973 311795 1974 354000 1975 230000 1976 416682 1977 656000 1978 631983 1979 606948