Year	Number
1859	0
1860	0
1861	0
1862	0
1863	0
1864	-2
1865	-2
1866	-7
1867	-7
1868	-7
1869	-7
1870	-7
1871	-7
1872	-7
1873	-7
1874	-7
1875	-7
1876	-7
1877	-7
1878	-7
1879	-7
1880	-7
1881	-7
1882	-7
1883	-7
1884	-7
1885	-7
1886	-7
1887	-7
1888	-7
1889	-7
1890	-7
1891	-7
1892	-7
1893	-7
1894	-7
1895	-7
1896	-7
1897	-7
1898	-7
1899	-7
1900	-6
1901	-6
1902	-6
1903	-6
1904	-6
1905	-6
1906	-6
1907	-6
1908	-6
1909	-6
1910	-4
1911	-4
1912	-4
1913	-4
1914	-4
1915	-4
1916	-4
1917	-4
1918	-4
1919	-4
1920	-4
1921	-4
1922	-4
1923	-4
1924	-4
1925	-4
1926	-4
1927	-4
1928	-4
1929	-4
1930	-4
1931	-4
1932	-4
1933	-4
1934	-4
1935	-4
1936	-4
1937	-4
1938	-6
1939	-6
1940	-7
1941	-7
1942	-7
1943	-7
1944	-7
1945	-7
1946	-7
1947	-7
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	-7
1969	-7
1970	-7
1971	-7
1972	-7
1973	-7
1974	-7
1975	-7
1976	-7
1977	-8
1978	-8
1979	-8
1980	-8
1981	-8
1982	-8
1983	-8
1984	-8
1985	-8
1986	-8
1987	-8
1988	-8
1989	-2
1990	5
1991	5
1992	5
1993	5
1994	5
1995	5
1996	8
1997	8
1998	8
1999	8
2000	8
2001	8
2002	8
2003	8
2004	9
2005	9
2006	9
2007	9
2008	9
2009	9
2010	9
2011	9