Year	Number
1922	4
1923	4
1924	4
1925	4
1926	4
1927	4
1928	1
1929	-3
1930	-6
1931	-6
1932	-6
1933	-6
1934	-2
1935	1
1936	1
1937	1
1938	1
1939	1
1940	1
1941	1
1942	1
1943	1
1944	1
1945	1
1946	1
1947	1
1948	1
1949	1
1950	1
1951	1
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	-6
1977	-6
1978	-6
1979	-6
1980	-6
1981	-6
1982	-6
1983	-6
1984	-6
1985	-6
1986	-6
1987	-6
1988	-6
1989	-6
1990	-6
1991	-6
1992	-6
1993	-6
1994	-6
1995	-6
1996	-6
1997	-6
1998	-6
1999	-6
2000	-6
2001	-6
2002	-6
2003	-6
2004	-6
2005	-3
2006	-3
2007	-3
2008	-3
2009	-3
2010	-3
2011	-2