Year Total 1800 6.75 1801 6.75 1802 6.75 1803 6.75 1804 6.75 1805 6.75 1806 6.75 1807 6.75 1808 6.75 1809 6.75 1810 6.75 1811 6.75 1812 6.75 1813 6.75 1814 6.75 1815 6.75 1816 6.75 1817 6.75 1818 6.75 1819 6.75 1820 6.75 1821 6.75 1822 6.75 1823 6.75 1824 6.75 1825 6.75 1826 6.75 1827 6.75 1828 6.75 1829 6.75 1830 6.75 1831 6.75 1832 6.75 1833 6.75 1834 6.75 1835 6.75 1836 6.75 1837 6.75 1838 6.75 1839 6.75 1840 6.75 1841 6.75 1842 6.75 1843 6.75 1844 6.75 1845 6.75 1846 6.75 1847 6.75 1848 6.75 1849 6.75 1850 6.75 1851 6.75 1852 6.75 1853 6.75 1854 6.75 1855 6.75 1856 6.75 1857 6.75 1858 6.75 1859 6.75 1860 6.75 1861 6.75 1862 6.75 1863 6.75 1864 6.75 1865 6.75 1866 6.75 1867 6.75 1868 6.75 1869 6.75 1870 6.75 1871 6.75 1872 6.75 1873 6.75 1874 6.75 1875 6.75 1876 6.75 1877 6.75 1878 6.75 1879 6.75 1880 6.75 1881 6.75 1882 6.75 1883 6.75 1884 6.75 1885 6.75 1886 6.75 1887 6.75 1888 6.75 1889 6.75 1890 6.75 1891 6.75 1892 6.75 1893 6.75 1894 6.75 1895 6.75 1896 6.75 1897 6.75 1898 6.75 1899 6.75 1900 6.75 1901 6.75 1902 6.75 1903 6.75 1904 6.75 1905 6.75 1906 6.75 1907 6.75 1908 6.75 1909 6.75 1910 6.75 1911 6.75 1912 6.75 1913 6.75 1914 6.75 1915 6.75 1916 6.75 1917 6.75 1918 6.75 1919 6.75 1920 6.75 1921 6.75 1922 6.75 1923 6.75 1924 6.75 1925 6.75 1926 6.75 1927 6.75 1928 6.75 1929 6.75 1930 6.75 1931 6.75 1932 6.75 1933 6.75 1934 6.75 1935 6.75 1936 6.75 1937 6.75 1938 6.75 1939 6.75 1940 6.75 1941 6.75 1942 6.75 1943 6.75 1944 6.75 1945 6.75 1946 6.75 1947 6.75 1948 6.75 1949 6.75 1950 6.75 1951 6.76 1952 6.78 1953 6.81 1954 6.84 1955 6.88 1956 6.93 1957 6.98 1958 7.04 1959 7.1 1960 7.16 1961 7.22 1962 7.27 1963 7.31 1964 7.35 1965 7.37 1966 7.39 1967 7.4 1968 7.41 1969 7.42 1970 7.42 1971 7.42 1972 7.42 1973 7.42 1974 7.41 1975 7.4 1976 7.37 1977 7.33 1978 7.27 1979 7.2 1980 7.1 1981 6.97 1982 6.81 1983 6.63 1984 6.44 1985 6.22 1986 6 1987 5.78 1988 5.57 1989 5.37 1990 5.18 1991 5 1992 4.84 1993 4.69 1994 4.56 1995 4.43 1996 4.33 1997 4.24 1998 4.16 1999 4.1 2000 4.06 2001 4.02 2002 4 2003 3.99 2004 3.98 2005 3.99 2006 3.99 2007 4 2008 4.01 2009 4.02 2010 4.03 2011 4.02 2012 4 2013 3.96 2014 3.9 2015 3.84 2016 3.76 2017 3.68 2018 3.61