Year Total 1800 5.51 1801 5.51 1802 5.51 1803 5.51 1804 5.51 1805 5.51 1806 5.51 1807 5.51 1808 5.51 1809 5.51 1810 5.51 1811 5.51 1812 5.51 1813 5.51 1814 5.51 1815 5.51 1816 5.51 1817 5.51 1818 5.51 1819 5.51 1820 5.51 1821 5.51 1822 5.51 1823 5.51 1824 5.51 1825 5.51 1826 5.51 1827 5.51 1828 5.51 1829 5.51 1830 5.51 1831 5.51 1832 5.51 1833 5.51 1834 5.51 1835 5.51 1836 5.51 1837 5.51 1838 5.51 1839 5.51 1840 5.51 1841 5.51 1842 5.51 1843 5.51 1844 5.51 1845 5.51 1846 5.51 1847 5.51 1848 5.51 1849 5.51 1850 5.51 1851 5.51 1852 5.51 1853 5.51 1854 5.51 1855 5.51 1856 5.51 1857 5.51 1858 5.51 1859 5.51 1860 5.51 1861 5.51 1862 5.51 1863 5.51 1864 5.51 1865 5.51 1866 5.51 1867 5.51 1868 5.51 1869 5.51 1870 5.51 1871 5.51 1872 5.51 1873 5.51 1874 5.51 1875 5.51 1876 5.51 1877 5.51 1878 5.51 1879 5.51 1880 5.51 1881 5.51 1882 5.51 1883 5.51 1884 5.51 1885 5.51 1886 5.51 1887 5.51 1888 5.51 1889 5.51 1890 5.51 1891 5.51 1892 5.51 1893 5.51 1894 5.51 1895 5.51 1896 5.51 1897 5.51 1898 5.51 1899 5.51 1900 5.51 1901 5.51 1902 5.51 1903 5.51 1904 5.51 1905 5.51 1906 5.51 1907 5.51 1908 5.51 1909 5.51 1910 5.51 1911 5.51 1912 5.51 1913 5.51 1914 5.51 1915 5.51 1916 5.51 1917 5.51 1918 5.51 1919 5.51 1920 5.51 1921 5.51 1922 5.51 1923 5.51 1924 5.51 1925 5.51 1926 5.51 1927 5.51 1928 5.51 1929 5.51 1930 5.51 1931 5.51 1932 5.51 1933 5.51 1934 5.51 1935 5.51 1936 5.52 1937 5.52 1938 5.52 1939 5.52 1940 5.53 1941 5.53 1942 5.53 1943 5.54 1944 5.54 1945 5.55 1946 5.56 1947 5.56 1948 5.57 1949 5.57 1950 5.58 1951 5.59 1952 5.59 1953 5.6 1954 5.6 1955 5.61 1956 5.61 1957 5.62 1958 5.63 1959 5.64 1960 5.65 1961 5.66 1962 5.67 1963 5.69 1964 5.71 1965 5.73 1966 5.76 1967 5.78 1968 5.79 1969 5.8 1970 5.81 1971 5.81 1972 5.81 1973 5.8 1974 5.8 1975 5.79 1976 5.79 1977 5.8 1978 5.8 1979 5.82 1980 5.84 1981 5.86 1982 5.88 1983 5.9 1984 5.93 1985 5.95 1986 5.96 1987 5.97 1988 5.98 1989 5.99 1990 5.99 1991 5.99 1992 5.98 1993 5.98 1994 5.98 1995 5.97 1996 5.96 1997 5.94 1998 5.91 1999 5.88 2000 5.83 2001 5.79 2002 5.73 2003 5.68 2004 5.62 2005 5.56 2006 5.5 2007 5.43 2008 5.36 2009 5.29 2010 5.21 2011 5.13 2012 5.04 2013 4.95 2014 4.86 2015 4.78 2016 4.69 2017 4.6 2018 4.51