Year	Number
1841	-1
1842	-1
1843	-1
1844	-1
1845	-1
1846	-1
1847	-1
1848	-1
1849	-1
1850	-1
1851	-1
1852	-1
1853	-1
1854	-1
1855	-1
1856	-1
1857	-1
1858	-1
1859	-1
1860	-1
1861	-1
1862	-1
1863	-1
1864	-1
1865	-1
1866	-1
1867	-1
1868	-1
1869	-1
1870	-1
1871	-1
1872	-1
1873	-1
1874	-1
1875	-1
1876	-1
1877	-1
1878	-1
1879	-1
1880	-1
1881	-1
1882	-1
1883	-1
1884	-1
1885	-1
1886	-1
1887	-1
1888	-1
1889	-1
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	-6
1904	-6
1905	-6
1906	-6
1907	-6
1908	-6
1909	-6
1910	-6
1911	-6
1912	-6
1913	-6
1914	-6
1915	-6
1916	-6
1917	-6
1918	-6
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	-9
1932	-9
1933	-9
1934	-9
1935	-9
1936	-9
1937	-9
1938	-9
1939	-9
1940	-9
1941	-9
1942	-9
1943	-9
1944	-8
1945	-8
1946	-8
1947	-8
1948	-7
1949	-7
1950	-6
1951	-6
1952	-6
1953	-6
1954	-6
1955	-6
1956	-5
1957	-5
1958	-5
1959	-5
1960	-3
1961	-3
1962	-3
1963	-3
1964	0
1965	0
1966	0
1967	0
1968	0
1969	0
1970	0
1971	0
1972	-1
1973	-1
1974	-1
1975	-1
1976	-1
1977	-6
1978	-6
1979	-4
1980	-2
1981	0
1982	2
1983	4
1984	6
1985	6
1986	6
1987	6
1988	6
1989	6
1990	6
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	8
2010	8
2011	8