Year Total 1800 4.97 1801 4.6 1802 5.3 1803 5.61 1804 5.65 1805 5.55 1806 5.49 1807 5.45 1808 5.4 1809 5.24 1810 5.36 1811 5.43 1812 5.31 1813 5.45 1814 5.46 1815 6.02 1816 5.73 1817 5.69 1818 5.54 1819 5.45 1820 5.4 1821 5.55 1822 5.69 1823 5.54 1824 5.42 1825 5.38 1826 5.36 1827 5.07 1828 5.23 1829 4.85 1830 4.83 1831 4.78 1832 4.78 1833 5 1834 4.89 1835 4.83 1836 4.86 1837 4.79 1838 4.78 1839 4.93 1840 4.9 1841 4.89 1842 4.83 1843 4.82 1844 4.83 1845 4.75 1846 4.9 1847 4.58 1848 4.71 1849 4.78 1850 4.85 1851 4.94 1852 4.94 1853 4.78 1854 4.89 1855 4.85 1856 4.94 1857 4.9 1858 4.79 1859 4.97 1860 4.86 1861 4.88 1862 4.92 1863 4.94 1864 4.96 1865 4.94 1866 4.92 1867 4.94 1868 4.97 1869 4.82 1870 4.88 1871 4.85 1872 4.89 1873 4.94 1874 4.93 1875 4.92 1876 4.9 1877 4.89 1878 4.88 1879 4.81 1880 4.75 1881 4.68 1882 4.62 1883 4.55 1884 4.47 1885 4.39 1886 4.32 1887 4.24 1888 4.16 1889 4.11 1890 4.06 1891 4 1892 3.95 1893 3.9 1894 3.84 1895 3.79 1896 3.73 1897 3.68 1898 3.62 1899 3.58 1900 3.53 1901 3.49 1902 3.44 1903 3.4 1904 3.35 1905 3.3 1906 3.24 1907 3.19 1908 3.14 1909 3.07 1910 2.99 1911 2.92 1912 2.9 1913 2.93 1914 2.88 1915 2.59 1916 2.6 1917 2.1 1918 2.03 1919 2.31 1920 3.08 1921 2.69 1922 2.44 1923 2.38 1924 2.28 1925 2.2 1926 2.15 1927 2.01 1928 2.01 1929 1.95 1930 1.95 1931 1.89 1932 1.83 1933 1.72 1934 1.76 1935 1.75 1936 1.77 1937 1.79 1938 1.84 1939 1.84 1940 1.74 1941 1.72 1942 1.93 1943 2.03 1944 2.25 1945 2.05 1946 2.47 1947 2.7 1948 2.39 1949 2.26 1950 2.08 1951 2.1 1952 2.15 1953 2.2 1954 2.26 1955 2.33 1956 2.4 1957 2.48 1958 2.55 1959 2.63 1960 2.69 1961 2.75 1962 2.79 1963 2.8 1964 2.79 1965 2.76 1966 2.7 1967 2.61 1968 2.52 1969 2.41 1970 2.29 1971 2.18 1972 2.07 1973 1.98 1974 1.89 1975 1.83 1976 1.78 1977 1.74 1978 1.73 1979 1.72 1980 1.73 1981 1.74 1982 1.76 1983 1.78 1984 1.8 1985 1.81 1986 1.82 1987 1.83 1988 1.83 1989 1.82 1990 1.81 1991 1.8 1992 1.79 1993 1.78 1994 1.77 1995 1.76 1996 1.74 1997 1.73 1998 1.71 1999 1.69 2000 1.68 2001 1.67 2002 1.67 2003 1.69 2004 1.72 2005 1.76 2006 1.8 2007 1.84 2008 1.86 2009 1.88 2010 1.89 2011 1.89 2012 1.89 2013 1.88 2014 1.88 2015 1.88 2016 1.87 2017 1.87 2018 1.87