Year	Total
1800	6.8
1801	6.8
1802	6.8
1803	6.8
1804	6.8
1805	6.8
1806	6.8
1807	6.8
1808	6.8
1809	6.8
1810	6.8
1811	6.8
1812	6.8
1813	6.8
1814	6.8
1815	6.8
1816	6.8
1817	6.8
1818	6.8
1819	6.8
1820	6.8
1821	6.8
1822	6.8
1823	6.8
1824	6.8
1825	6.8
1826	6.8
1827	6.8
1828	6.8
1829	6.8
1830	6.8
1831	6.8
1832	6.8
1833	6.8
1834	6.8
1835	6.8
1836	6.8
1837	6.8
1838	6.8
1839	6.8
1840	6.8
1841	6.8
1842	6.8
1843	6.8
1844	6.8
1845	6.8
1846	6.8
1847	6.8
1848	6.8
1849	6.8
1850	6.8
1851	6.8
1852	6.8
1853	6.8
1854	6.8
1855	6.8
1856	6.8
1857	6.8
1858	6.8
1859	6.8
1860	6.8
1861	6.8
1862	6.8
1863	6.81
1864	6.81
1865	6.81
1866	6.81
1867	6.81
1868	6.81
1869	6.81
1870	6.81
1871	6.81
1872	6.81
1873	6.81
1874	6.81
1875	6.81
1876	6.81
1877	6.81
1878	6.81
1879	6.81
1880	6.81
1881	6.81
1882	6.81
1883	6.81
1884	6.81
1885	6.81
1886	6.81
1887	6.81
1888	6.81
1889	6.81
1890	6.81
1891	6.81
1892	6.81
1893	6.81
1894	6.81
1895	6.81
1896	6.81
1897	6.81
1898	6.81
1899	6.81
1900	6.81
1901	6.81
1902	6.81
1903	6.81
1904	6.81
1905	6.81
1906	6.81
1907	6.81
1908	6.81
1909	6.81
1910	6.81
1911	6.81
1912	6.81
1913	6.81
1914	6.81
1915	6.81
1916	6.81
1917	6.81
1918	6.81
1919	6.81
1920	6.81
1921	6.81
1922	6.81
1923	6.81
1924	6.81
1925	6.81
1926	6.81
1927	6.81
1928	6.81
1929	6.81
1930	6.81
1931	6.81
1932	6.81
1933	6.81
1934	6.81
1935	6.81
1936	6.81
1937	6.81
1938	6.82
1939	6.82
1940	6.82
1941	6.82
1942	6.82
1943	6.82
1944	6.82
1945	6.82
1946	6.82
1947	6.82
1948	6.82
1949	6.82
1950	6.82
1951	6.81
1952	6.8
1953	6.79
1954	6.79
1955	6.8
1956	6.82
1957	6.85
1958	6.88
1959	6.91
1960	6.95
1961	7
1962	7.05
1963	7.09
1964	7.14
1965	7.18
1966	7.22
1967	7.25
1968	7.27
1969	7.28
1970	7.29
1971	7.3
1972	7.31
1973	7.33
1974	7.35
1975	7.37
1976	7.39
1977	7.41
1978	7.42
1979	7.42
1980	7.42
1981	7.42
1982	7.42
1983	7.44
1984	7.46
1985	7.49
1986	7.51
1987	7.53
1988	7.53
1989	7.53
1990	7.51
1991	7.47
1992	7.43
1993	7.39
1994	7.34
1995	7.29
1996	7.24
1997	7.18
1998	7.13
1999	7.07
2000	7.01
2001	6.95
2002	6.89
2003	6.82
2004	6.76
2005	6.69
2006	6.62
2007	6.53
2008	6.45
2009	6.35
2010	6.26
2011	6.16
2012	6.06
2013	5.96
2014	5.87
2015	5.78
2016	5.7
2017	5.62
2018	5.53