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	-9
1976	-9
1977	-9
1978	-9
1979	-9
1980	-9
1981	-9
1982	-9
1983	-9
1984	-9
1985	-9
1986	-9
1987	-9
1988	-9
1989	-9
1990	-7
1991	-7
1992	-7
1993	-7
1994	-6
1995	-6
1996	-6
1997	-6
1998	-6
1999	-1
2000	4
2001	4
2002	0
2003	0
2004	0
2005	0
2006	0
2007	0
2008	0
2009	0
2010	0
2011	0