Year	Number
1948	8
1949	8
1950	8
1951	8
1952	8
1953	8
1954	8
1955	8
1956	8
1957	8
1958	8
1959	8
1960	8
1961	8
1962	-6
1963	-7
1964	-7
1965	-7
1966	-7
1967	-7
1968	-7
1969	-7
1970	-7
1971	-7
1972	-7
1973	-7
1974	-6
1975	-6
1976	-6
1977	-6
1978	-6
1979	-6
1980	-8
1981	-8
1982	-8
1983	-8
1984	-8
1985	-8
1986	-8
1987	-8
1988	-6
1989	-6
1990	-7
1991	-7
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	-8
2005	-8
2006	-8
2007	-8
2008	-6
2009	-6
2010	-6
2011	-3