Year	Number
1920	7
1921	7
1922	7
1923	7
1924	7
1925	7
1926	7
1927	7
1928	7
1929	7
1930	7
1931	7
1932	7
1933	7
1934	-9
1935	-9
1936	-9
1937	-9
1938	-9
1939	-9
1940	-9
1941	-9
1942	-9
1943	-9
1944	-9
1945	-9
1946	-9
1947	-9
1948	-9
1949	-9
1950	-9
1951	-9
1952	-9
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	-6
1989	-4
1990	0
1991	8
1992	8
1993	8
1994	8
1995	8
1996	8
1997	8
1998	8
1999	8
2000	8
2001	8
2002	8
2003	8
2004	8
2005	8
2006	8
2007	8
2008	8
2009	8
2010	8
2011	8