Year	Years
1800	30.8
1801	30.8
1802	30.8
1803	30.8
1804	30.8
1805	30.8
1806	30.8
1807	30.8
1808	30.8
1809	30.8
1810	30.8
1811	30.8
1812	30.8
1813	30.8
1814	30.8
1815	30.8
1816	30.8
1817	30.8
1818	30.8
1819	30.8
1820	30.8
1821	30.8
1822	30.8
1823	30.8
1824	30.8
1825	30.8
1826	30.8
1827	30.8
1828	30.8
1829	30.8
1830	30.8
1831	30.8
1832	30.8
1833	30.8
1834	30.8
1835	30.8
1836	30.8
1837	30.8
1838	30.8
1839	30.8
1840	30.8
1841	30.8
1842	30.8
1843	30.8
1844	30.8
1845	30.8
1846	30.8
1847	30.8
1848	30.8
1849	30.8
1850	30.8
1851	30.8
1852	30.8
1853	30.8
1854	30.8
1855	30.8
1856	30.8
1857	30.8
1858	30.8
1859	30.8
1860	30.8
1861	30.8
1862	30.8
1863	30.8
1864	30.8
1865	30.8
1866	30.8
1867	30.8
1868	30.8
1869	30.8
1870	30.8
1871	30.8
1872	30.79
1873	30.79
1874	30.78
1875	30.78
1876	30.77
1877	30.77
1878	30.77
1879	30.76
1880	30.76
1881	30.75
1882	30.75
1883	30.74
1884	30.74
1885	30.74
1886	30.73
1887	30.73
1888	30.72
1889	30.72
1890	30.71
1891	30.71
1892	30.7
1893	30.7
1894	30.7
1895	30.69
1896	30.69
1897	30.68
1898	30.68
1899	30.67
1900	30.67
1901	30.67
1902	30.66
1903	30.66
1904	30.65
1905	30.65
1906	30.64
1907	30.64
1908	30.64
1909	30.63
1910	30.63
1911	30.62
1912	30.62
1913	30.61
1914	30.61
1915	30.61
1916	30.6
1917	30.6
1918	25.36
1919	30.59
1920	30.58
1921	30.58
1922	30.57
1923	30.57
1924	30.57
1925	30.56
1926	30.56
1927	30.55
1928	30.55
1929	30.54
1930	30.54
1931	30.54
1932	30.53
1933	30.53
1934	30.52
1935	30.52
1936	30.51
1937	30.51
1938	30.51
1939	30.5
1940	30.5
1941	32.75
1942	35
1943	37.25
1944	39.5
1945	41.76
1946	44
1947	46.25
1948	48.5
1949	50.76
1950	53.01
1951	53.41
1952	54.21
1953	55.01
1954	55.79
1955	56.58
1956	57.34
1957	58.1
1958	58.85
1959	59.6
1960	60.34
1961	61.08
1962	61.82
1963	62.56
1964	63.29
1965	64.02
1966	64.73
1967	65.44
1968	66.12
1969	66.77
1970	67.38
1971	67.42
1972	67.47
1973	67.53
1974	68.13
1975	68.7
1976	69.38
1977	69.92
1978	70.35
1979	70.69
1980	70.8
1981	70.92
1982	70.74
1983	71.49
1984	72.8
1985	73.1
1986	73.54
1987	73.99
1988	74.23
1989	74.73
1990	75.04
1991	74.93
1992	74.98
1993	74.88
1994	74.8
1995	74.79
1996	74.9
1997	74.99
1998	75.06
1999	75.1
2000	75.31
2001	75.59
2002	75.7
2003	75.95
2004	76.41
2005	76.88
2006	77.36
2007	77.88
2008	78.37
2009	78.9
2010	79.52
2011	79.97
2012	80.22
2013	80.49
2014	80.49
2015	80.46
2016	80.41
2017	80.56
2018	80.71