1950
1960
1950
1971
1961
1972
1951
1968
1965
1978
1962
1968
1965
1964
1973
1972
1961
1972
1964
1974
1991
1972
1980
1952
1972
1953
1952
1966
1970
1967
1976
1976
1976
1974
1979
1973
1977
1977
1988
1973
1982
1988
1976
1962
1955
1970
1971
1978
1975
1967
1976
1972
1976
1981
1988
1989
1965
1997
1993
1997
1990
1982
1990
1991
1990
1986
1988
1988
1990
1989
1987
1996
1972
1969
1995
1970
1958
1970
1961
1975
1974
1963
1977
1966
1968
1985
1978
1991
1991
1968
1968
1974
1961
1974
1978
1981
1966
1971
1951
1957
1970
1957
1984
1967
1988
1990
1992
1991
1994
1990
1978
Comments