1951 1956 1956 1958 1960 1960 1960 1960—1961 1961 1962 1962 1963 1963 1963 1965 1977 1977 1978 1979 1979 1981 1983 1983 1984 1984 1984 1984 1985 1985 1985 1985 1986 1986 1987 1987 1987 1988 1988 1988 1988 1990 1991 1992 1995 1997 