Year	Number
1918	7
1919	7
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	7
1935	7
1936	7
1937	7
1938	7
1939	0
1940	0
1941	0
1942	0
1943	0
1944	0
1945	10
1946	10
1947	2
1948	-7
1949	-7
1950	-7
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	0
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	-6
1990	8
1991	8
1992	8
1993	10
1994	10
1995	10
1996	10
1997	10
1998	10
1999	10
2000	10
2001	10
2002	10
2003	10
2004	10
2005	10
2006	8
2007	8
2008	8
2009	8
2010	8
2011	8