Year	Number
1963	-8
1964	-8
1965	-9
1966	-9
1967	-9
1968	-9
1969	-9
1970	-9
1971	-8
1972	-8
1973	-8
1974	-8
1975	-8
1976	-10
1977	-10
1978	-10
1979	-10
1980	-10
1981	-8
1982	-8
1983	-8
1984	-8
1985	-8
1986	-10
1987	-10
1988	-10
1989	-10
1990	-10
1991	-9
1992	-7
1993	-7
1994	-7
1995	-7
1996	-7
1997	-7
1998	-7
1999	-7
2000	-7
2001	-7
2002	-7
2003	-7
2004	-7
2005	-7
2006	-7
2007	-7
2008	-7
2009	-7
2010	-7
2011	-7