Year	Number
1830	-1
1831	-1
1832	-1
1833	-1
1834	-1
1835	-1
1836	-1
1837	-1
1838	-1
1839	-1
1840	-1
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	-3
1902	-3
1903	-3
1904	-3
1905	-3
1906	-3
1907	-3
1908	-3
1909	-3
1910	-3
1911	-3
1912	-3
1913	-3
1914	-3
1915	-3
1916	-3
1917	-3
1918	-3
1919	-3
1920	-3
1921	-3
1922	-3
1923	-3
1924	-3
1925	-1
1926	-1
1927	-1
1928	-1
1929	-1
1930	-1
1931	-1
1932	-1
1933	-1
1934	-1
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	2
1949	2
1950	2
1951	2
1952	2
1953	2
1954	2
1955	2
1956	2
1957	2
1958	2
1959	2
1960	2
1961	-1
1962	-1
1963	-1
1964	-1
1965	-1
1966	-1
1967	-1
1968	5
1969	5
1970	0
1971	0
1972	-5
1973	-5
1974	-5
1975	-5
1976	-5
1977	-5
1978	-5
1979	9
1980	9
1981	9
1982	9
1983	9
1984	8
1985	8
1986	8
1987	8
1988	9
1989	9
1990	9
1991	9
1992	9
1993	9
1994	9
1995	9
1996	9
1997	8
1998	9
1999	9
2000	6
2001	6
2002	6
2003	6
2004	6
2005	6
2006	7
2007	5
2008	5
2009	5
2010	5
2011	5