Year Total 1800 6.86 1801 6.86 1802 6.86 1803 6.86 1804 6.86 1805 6.86 1806 6.86 1807 6.86 1808 6.86 1809 6.86 1810 6.86 1811 6.86 1812 6.86 1813 6.86 1814 6.86 1815 6.86 1816 6.86 1817 6.86 1818 6.86 1819 6.86 1820 6.86 1821 6.86 1822 6.86 1823 6.86 1824 6.86 1825 6.86 1826 6.86 1827 6.86 1828 6.86 1829 6.86 1830 6.86 1831 6.86 1832 6.86 1833 6.86 1834 6.86 1835 6.86 1836 6.86 1837 6.86 1838 6.86 1839 6.86 1840 6.86 1841 6.86 1842 6.86 1843 6.86 1844 6.86 1845 6.86 1846 6.86 1847 6.86 1848 6.86 1849 6.86 1850 6.86 1851 6.86 1852 6.86 1853 6.86 1854 6.86 1855 6.86 1856 6.86 1857 6.86 1858 6.86 1859 6.86 1860 6.86 1861 6.86 1862 6.86 1863 6.86 1864 6.86 1865 6.86 1866 6.86 1867 6.86 1868 6.86 1869 6.86 1870 6.86 1871 6.86 1872 6.86 1873 6.86 1874 6.86 1875 6.86 1876 6.86 1877 6.86 1878 6.86 1879 6.86 1880 6.86 1881 6.86 1882 6.86 1883 6.86 1884 6.86 1885 6.86 1886 6.86 1887 6.86 1888 6.86 1889 6.86 1890 6.86 1891 6.86 1892 6.86 1893 6.86 1894 6.86 1895 6.86 1896 6.86 1897 6.86 1898 6.86 1899 6.86 1900 6.86 1901 6.86 1902 6.86 1903 6.86 1904 6.86 1905 6.86 1906 6.86 1907 6.86 1908 6.86 1909 6.86 1910 6.86 1911 6.86 1912 6.86 1913 6.86 1914 6.86 1915 6.86 1916 6.86 1917 6.86 1918 6.86 1919 6.86 1920 6.86 1921 6.86 1922 6.86 1923 6.86 1924 6.86 1925 6.86 1926 6.87 1927 6.89 1928 6.9 1929 6.91 1930 6.93 1931 6.94 1932 6.96 1933 6.97 1934 6.98 1935 7 1936 7.01 1937 7.02 1938 7.04 1939 7.05 1940 7.06 1941 7.08 1942 7.09 1943 7.1 1944 7.12 1945 7.13 1946 7.15 1947 7.16 1948 7.17 1949 7.19 1950 7.2 1951 7.19 1952 7.18 1953 7.17 1954 7.16 1955 7.16 1956 7.17 1957 7.17 1958 7.19 1959 7.2 1960 7.22 1961 7.23 1962 7.24 1963 7.25 1964 7.26 1965 7.26 1966 7.26 1967 7.26 1968 7.27 1969 7.27 1970 7.28 1971 7.29 1972 7.3 1973 7.31 1974 7.31 1975 7.31 1976 7.31 1977 7.3 1978 7.28 1979 7.25 1980 7.21 1981 7.14 1982 7.05 1983 6.93 1984 6.8 1985 6.65 1986 6.5 1987 6.34 1988 6.19 1989 6.05 1990 5.91 1991 5.76 1992 5.59 1993 5.41 1994 5.2 1995 4.98 1996 4.75 1997 4.53 1998 4.33 1999 4.14 2000 3.97 2001 3.83 2002 3.71 2003 3.6 2004 3.51 2005 3.42 2006 3.33 2007 3.24 2008 3.15 2009 3.06 2010 2.96 2011 2.87 2012 2.78 2013 2.7 2014 2.64 2015 2.58 2016 2.53 2017 2.49 2018 2.45