Year	Number
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	-7
1978	-3
1979	0
1980	0
1981	0
1982	0
1983	0
1984	-4
1985	-7
1986	-7
1987	-7
1988	-7
1989	-7
1990	-7
1991	-5
1992	-4
1993	-4
1994	-4
1995	-4
1996	-2
1997	-2
1998	-2
1999	-2
2000	-2
2001	-2
2002	-2
2003	-2
2004	-2
2005	-2
2006	-2
2007	-2
2008	-2
2009	-2
2010	-2
2011	-2