Year	Years
1800	31.9
1801	31.9
1802	31.9
1803	31.9
1804	31.9
1805	31.9
1806	31.9
1807	31.9
1808	31.9
1809	31.9
1810	31.9
1811	31.9
1812	31.9
1813	31.9
1814	31.9
1815	31.9
1816	31.9
1817	31.9
1818	31.9
1819	31.9
1820	31.9
1821	31.9
1822	31.9
1823	31.9
1824	31.9
1825	31.9
1826	31.9
1827	31.9
1828	31.9
1829	31.9
1830	31.9
1831	31.9
1832	31.9
1833	31.9
1834	31.9
1835	31.9
1836	31.9
1837	31.9
1838	31.9
1839	31.9
1840	31.9
1841	31.9
1842	31.9
1843	31.9
1844	31.9
1845	31.9
1846	31.9
1847	31.9
1848	31.9
1849	31.9
1850	31.9
1851	31.9
1852	31.9
1853	31.9
1854	31.9
1855	31.9
1856	31.9
1857	31.9
1858	31.9
1859	31.9
1860	31.9
1861	31.9
1862	31.9
1863	31.9
1864	31.9
1865	31.9
1866	31.9
1867	31.9
1868	31.9
1869	31.9
1870	31.9
1871	31.87
1872	31.84
1873	31.82
1874	31.79
1875	31.76
1876	31.73
1877	31.7
1878	31.67
1879	31.65
1880	31.62
1881	31.59
1882	31.56
1883	31.53
1884	31.5
1885	31.48
1886	31.45
1887	31.42
1888	31.39
1889	31.36
1890	31.33
1891	31.31
1892	31.28
1893	31.25
1894	31.22
1895	31.19
1896	31.16
1897	31.14
1898	31.11
1899	31.08
1900	31.05
1901	31.02
1902	30.99
1903	30.97
1904	30.94
1905	30.91
1906	30.88
1907	30.85
1908	30.82
1909	30.8
1910	30.77
1911	30.74
1912	30.71
1913	30.68
1914	30.65
1915	30.63
1916	30.6
1917	30.57
1918	19.57
1919	30.51
1920	30.49
1921	30.46
1922	30.43
1923	30.4
1924	30.37
1925	30.34
1926	30.32
1927	30.29
1928	30.26
1929	30.23
1930	30.2
1931	30.17
1932	30.15
1933	30.12
1934	30.09
1935	30.06
1936	30.03
1937	30
1938	29.98
1939	29.95
1940	29.54
1941	29.23
1942	28.93
1943	28.15
1944	27.19
1945	25.2
1946	31.71
1947	33.54
1948	35.84
1949	36.72
1950	37.47
1951	37.56
1952	37.8
1953	38.04
1954	38.28
1955	38.52
1956	38.76
1957	39.01
1958	39.26
1959	39.49
1960	39.74
1961	39.99
1962	40.23
1963	40.47
1964	40.71
1965	40.95
1966	41.19
1967	41.43
1968	41.67
1969	41.91
1970	42.16
1971	42.6
1972	43.06
1973	43.54
1974	45.18
1975	45.67
1976	46.19
1977	46.58
1978	46.98
1979	47.4
1980	47.86
1981	48.43
1982	49
1983	49.59
1984	50.21
1985	50.7
1986	51.07
1987	51.43
1988	51.72
1989	52.16
1990	52.46
1991	52.96
1992	53.34
1993	53.66
1994	53.97
1995	54.52
1996	55.01
1997	55.52
1998	55.97
1999	56.54
2000	57.06
2001	57.55
2002	58.36
2003	59.02
2004	59.69
2005	60.28
2006	60.92
2007	61.67
2008	62.34
2009	63.06
2010	63.8
2011	64.56
2012	65.17
2013	65.71
2014	66.28
2015	66.78
2016	67.26
2017	67.6
2018	67.93