Year Total 1800 7.8 1801 7.8 1802 7.8 1803 7.8 1804 7.8 1805 7.8 1806 7.8 1807 7.8 1808 7.8 1809 7.8 1810 7.8 1811 7.8 1812 7.8 1813 7.8 1814 7.8 1815 7.8 1816 7.8 1817 7.8 1818 7.8 1819 7.8 1820 7.8 1821 7.8 1822 7.8 1823 7.8 1824 7.8 1825 7.8 1826 7.8 1827 7.8 1828 7.8 1829 7.8 1830 7.8 1831 7.8 1832 7.8 1833 7.8 1834 7.8 1835 7.8 1836 7.8 1837 7.8 1838 7.8 1839 7.8 1840 7.8 1841 7.8 1842 7.8 1843 7.8 1844 7.8 1845 7.8 1846 7.8 1847 7.8 1848 7.8 1849 7.8 1850 7.8 1851 7.8 1852 7.8 1853 7.8 1854 7.8 1855 7.8 1856 7.8 1857 7.8 1858 7.8 1859 7.8 1860 7.8 1861 7.8 1862 7.8 1863 7.8 1864 7.8 1865 7.8 1866 7.8 1867 7.8 1868 7.8 1869 7.8 1870 7.8 1871 7.8 1872 7.8 1873 7.8 1874 7.8 1875 7.8 1876 7.8 1877 7.8 1878 7.8 1879 7.8 1880 7.8 1881 7.8 1882 7.8 1883 7.8 1884 7.8 1885 7.8 1886 7.8 1887 7.8 1888 7.8 1889 7.8 1890 7.8 1891 7.8 1892 7.8 1893 7.8 1894 7.8 1895 7.8 1896 7.8 1897 7.8 1898 7.8 1899 7.8 1900 7.8 1901 7.72 1902 7.65 1903 7.57 1904 7.49 1905 7.42 1906 7.34 1907 7.26 1908 7.19 1909 7.11 1910 7.03 1911 6.96 1912 6.88 1913 6.8 1914 6.73 1915 6.65 1916 6.57 1917 6.5 1918 6.42 1919 6.34 1920 6.27 1921 6.19 1922 6.11 1923 6.04 1924 5.96 1925 5.88 1926 5.81 1927 5.73 1928 5.65 1929 5.58 1930 5.5 1931 5.32 1932 5.13 1933 4.95 1934 4.77 1935 4.59 1936 4.4 1937 4.22 1938 4.04 1939 3.85 1940 3.67 1941 3.61 1942 3.56 1943 3.5 1944 3.44 1945 3.39 1946 3.33 1947 3.27 1948 3.21 1949 3.16 1950 3.1 1951 3.04 1952 2.97 1953 2.92 1954 2.9 1955 2.89 1956 2.9 1957 2.91 1958 2.93 1959 2.94 1960 2.94 1961 2.94 1962 2.94 1963 2.92 1964 2.91 1965 2.88 1966 2.85 1967 2.82 1968 2.79 1969 2.75 1970 2.71 1971 2.67 1972 2.62 1973 2.58 1974 2.53 1975 2.49 1976 2.45 1977 2.41 1978 2.37 1979 2.34 1980 2.31 1981 2.3 1982 2.28 1983 2.28 1984 2.28 1985 2.27 1986 2.27 1987 2.26 1988 2.24 1989 2.22 1990 2.18 1991 2.13 1992 2.08 1993 2.01 1994 1.95 1995 1.88 1996 1.81 1997 1.75 1998 1.69 1999 1.64 2000 1.61 2001 1.59 2002 1.59 2003 1.6 2004 1.63 2005 1.66 2006 1.71 2007 1.77 2008 1.82 2009 1.87 2010 1.92 2011 1.95 2012 1.98 2013 2 2014 2 2015 2 2016 2 2017 1.99 2018 1.98