Year	Number
1868	-6
1869	-5
1870	-5
1871	-4
1872	-4
1873	-4
1874	-4
1875	-4
1876	-4
1877	-4
1878	-4
1879	-4
1880	-4
1881	-4
1882	-4
1883	-4
1884	-4
1885	-4
1886	-4
1887	-4
1888	-4
1889	-4
1890	1
1891	1
1892	1
1893	1
1894	1
1895	1
1896	1
1897	1
1898	1
1899	1
1900	1
1901	1
1902	1
1903	1
1904	1
1905	1
1906	1
1907	1
1908	1
1909	2
1910	2
1911	2
1912	2
1913	2
1914	2
1915	2
1916	2
1917	2
1918	4
1919	6
1920	6
1921	6
1922	6
1923	6
1924	6
1925	6
1926	6
1927	6
1928	6
1929	6
1930	6
1931	6
1932	6
1933	-9
1934	-9
1935	-9
1936	-9
1937	-9
1938	-9
1939	-9
1940	-9
1941	-9
1942	-9
1943	-9
1944	-9
1945	-5
1946	-1
1947	2
1948	6
1949	10
1950	10
1951	10
1952	10
1953	10
1954	10
1955	10
1956	10
1957	10
1958	10
1959	10
1960	10
1961	10
1962	10
1963	10
1964	10
1965	10
1966	10
1967	10
1968	10
1969	10
1970	10
1971	10
1972	10
1973	10
1974	10
1975	10
1976	10
1977	10
1978	10
1979	10
1980	10
1981	10
1982	10
1983	10
1984	10
1985	10
1986	10
1987	10
1988	10
1989	10
1990	10
1991	10
1992	10
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	10
2007	10
2008	10
2009	10
2010	10
2011	10