Year	Total
1800	6
1801	6
1802	6
1803	6
1804	6
1805	6
1806	6
1807	6
1808	6
1809	6
1810	6
1811	6
1812	6
1813	6
1814	6
1815	6
1816	6
1817	6
1818	6
1819	6
1820	6
1821	6
1822	6
1823	6
1824	6
1825	6
1826	6
1827	6
1828	6
1829	6
1830	6
1831	6
1832	6
1833	6
1834	6
1835	6
1836	6
1837	6
1838	6
1839	6
1840	6
1841	6
1842	6
1843	6
1844	6
1845	6
1846	6
1847	6
1848	6
1849	6
1850	6
1851	6
1852	6
1853	6
1854	6
1855	6
1856	6
1857	6
1858	6
1859	6
1860	6
1861	6
1862	6
1863	6
1864	6
1865	6
1866	6
1867	6
1868	6
1869	6
1870	6
1871	6
1872	6
1873	6
1874	6
1875	6
1876	6
1877	6
1878	6
1879	6
1880	6
1881	6
1882	6
1883	6
1884	6
1885	6
1886	6
1887	6
1888	6
1889	6
1890	6
1891	6
1892	6
1893	6
1894	6
1895	6
1896	6
1897	6
1898	6
1899	6
1900	6
1901	6
1902	5.99
1903	5.99
1904	5.98
1905	5.98
1906	5.97
1907	5.97
1908	5.96
1909	5.96
1910	5.96
1911	5.95
1912	5.95
1913	5.94
1914	5.94
1915	5.93
1916	5.93
1917	5.92
1918	5.92
1919	5.93
1920	5.94
1921	5.95
1922	5.96
1923	5.97
1924	5.95
1925	5.93
1926	5.91
1927	5.89
1928	5.87
1929	5.9
1930	5.93
1931	5.96
1932	6
1933	6.03
1934	6.08
1935	6.13
1936	6.18
1937	6.23
1938	6.29
1939	6.3
1940	6.31
1941	6.32
1942	6.34
1943	6.36
1944	6.3
1945	6.25
1946	6.19
1947	6.14
1948	6.09
1949	5.28
1950	4.46
1951	4.76
1952	5.25
1953	5.64
1954	5.94
1955	6.16
1956	6.28
1957	6.33
1958	6.31
1959	6.23
1960	6.1
1961	5.93
1962	5.74
1963	5.53
1964	5.33
1965	5.13
1966	4.94
1967	4.77
1968	4.62
1969	4.47
1970	4.34
1971	4.19
1972	4.04
1973	3.86
1974	3.67
1975	3.46
1976	3.25
1977	3.05
1978	2.87
1979	2.7
1980	2.54
1981	2.4
1982	2.26
1983	2.11
1984	1.97
1985	1.84
1986	1.73
1987	1.65
1988	1.6
1989	1.58
1990	1.58
1991	1.6
1992	1.63
1993	1.64
1994	1.64
1995	1.62
1996	1.58
1997	1.53
1998	1.47
1999	1.41
2000	1.35
2001	1.29
2002	1.25
2003	1.21
2004	1.18
2005	1.17
2006	1.16
2007	1.16
2008	1.17
2009	1.18
2010	1.19
2011	1.21
2012	1.22
2013	1.24
2014	1.26
2015	1.28
2016	1.3
2017	1.31
2018	1.33