Year	Number
1951	-7
1952	-7
1953	-7
1954	-7
1955	-7
1956	-7
1957	-7
1958	-7
1959	-7
1960	-7
1961	-7
1962	-7
1963	-7
1964	-7
1965	-7
1966	-7
1967	-7
1968	-7
1969	-7
1970	-7
1971	-7
1972	-7
1973	-7
1974	-7
1975	-7
1976	-7
1977	-7
1978	-7
1979	-7
1980	-7
1981	-7
1982	-7
1983	-7
1984	-7
1985	-7
1986	-7
1987	-7
1988	-7
1989	-7
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	-7
2005	-7
2006	-7
2007	-7
2008	-7
2009	-7
2010	-7
2011	0