Year	Total
1800	4.04
1801	4.04
1802	4.05
1803	4.05
1804	4.06
1805	4.06
1806	4.07
1807	4.07
1808	4.08
1809	4.09
1810	4.09
1811	4.1
1812	4.11
1813	4.12
1814	4.13
1815	4.14
1816	4.14
1817	4.15
1818	4.16
1819	4.17
1820	4.18
1821	4.19
1822	4.2
1823	4.21
1824	4.22
1825	4.23
1826	4.16
1827	4.1
1828	4.03
1829	3.97
1830	3.9
1831	3.92
1832	3.94
1833	3.96
1834	3.98
1835	4
1836	4.02
1837	4.04
1838	4.06
1839	4.08
1840	4.1
1841	4.12
1842	4.13
1843	4.15
1844	4.16
1845	4.17
1846	4.19
1847	4.2
1848	4.22
1849	4.23
1850	4.24
1851	4.06
1852	4.48
1853	4.27
1854	4.41
1855	4.31
1856	4.37
1857	4.44
1858	4.48
1859	4.53
1860	4.4
1861	4.27
1862	4.17
1863	4.17
1864	4.06
1865	4.21
1866	4.32
1867	4.09
1868	4.18
1869	3.96
1870	4.1
1871	4.06
1872	4.09
1873	4.16
1874	4.17
1875	4.31
1876	4.4
1877	4.36
1878	4.27
1879	4.3
1880	4.28
1881	4.34
1882	4.36
1883	4.29
1884	4.5
1885	4.39
1886	4.37
1887	4.28
1888	4.25
1889	4.21
1890	4.11
1891	4.18
1892	4
1893	4.16
1894	4.1
1895	4.09
1896	4.11
1897	4.02
1898	4.08
1899	4.01
1900	4.07
1901	4.14
1902	4.05
1903	3.96
1904	3.97
1905	3.87
1906	3.87
1907	3.81
1908	3.83
1909	3.78
1910	3.67
1911	3.6
1912	3.58
1913	3.43
1914	3.42
1915	3.23
1916	3.23
1917	3.11
1918	3.16
1919	2.96
1920	3.29
1921	3.11
1922	2.87
1923	2.86
1924	2.78
1925	2.66
1926	2.58
1927	2.44
1928	2.43
1929	2.3
1930	2.3
1931	2.2
1932	2.19
1933	2.1
1934	2.15
1935	2.12
1936	2.14
1937	2.16
1938	2.18
1939	2.16
1940	2.22
1941	2.24
1942	2.5
1943	2.65
1944	2.84
1945	2.98
1946	3.02
1947	2.9
1948	2.71
1949	2.57
1950	2.58
1951	2.5
1952	2.54
1953	2.6
1954	2.54
1955	2.58
1956	2.59
1957	2.56
1958	2.54
1959	2.49
1960	2.54
1961	2.55
1962	2.54
1963	2.64
1964	2.6
1965	2.61
1966	2.62
1967	2.35
1968	2.12
1969	2
1970	1.95
1971	2.04
1972	2.03
1973	1.92
1974	1.9
1975	1.92
1976	1.75
1977	1.66
1978	1.67
1979	1.6
1980	1.55
1981	1.44
1982	1.43
1983	1.38
1984	1.4
1985	1.45
1986	1.48
1987	1.5
1988	1.56
1989	1.62
1990	1.67
1991	1.68
1992	1.76
1993	1.75
1994	1.81
1995	1.81
1996	1.75
1997	1.75
1998	1.72
1999	1.74
2000	1.77
2001	1.75
2002	1.72
2003	1.76
2004	1.78
2005	1.8
2006	1.85
2007	1.85
2008	1.89
2009	1.84
2010	1.88
2011	1.76
2012	1.73
2013	1.88
2014	1.83
2015	1.79
2016	1.74
2017	1.75
2018	1.76