Year	Number
1950	9
1951	9
1952	9
1953	9
1954	9
1955	9
1956	9
1957	9
1958	9
1959	9
1960	9
1961	9
1962	9
1963	9
1964	9
1965	9
1966	9
1967	9
1968	9
1969	9
1970	9
1971	9
1972	9
1973	9
1974	9
1975	7
1976	7
1977	8
1978	8
1979	8
1980	8
1981	8
1982	8
1983	8
1984	8
1985	8
1986	8
1987	8
1988	8
1989	8
1990	8
1991	8
1992	8
1993	8
1994	8
1995	9
1996	9
1997	9
1998	9
1999	9
2000	9
2001	9
2002	9
2003	9
2004	9
2005	9
2006	9
2007	9
2008	9
2009	9
2010	9
2011	9