Year Total
1800 5.9
1801 5.9
1802 5.9
1803 5.9
1804 5.9
1805 5.9
1806 5.9
1807 5.9
1808 5.9
1809 5.9
1810 5.9
1811 5.9
1812 5.9
1813 5.9
1814 5.9
1815 5.9
1816 5.9
1817 5.9
1818 5.9
1819 5.9
1820 5.9
1821 5.9
1822 5.9
1823 5.9
1824 5.9
1825 5.9
1826 5.9
1827 5.9
1828 5.9
1829 5.9
1830 5.9
1831 5.9
1832 5.9
1833 5.9
1834 5.9
1835 5.9
1836 5.9
1837 5.9
1838 5.9
1839 5.9
1840 5.9
1841 5.9
1842 5.9
1843 5.9
1844 5.9
1845 5.9
1846 5.9
1847 5.9
1848 5.9
1849 5.9
1850 5.9
1851 5.9
1852 5.9
1853 5.9
1854 5.9
1855 5.9
1856 5.9
1857 5.9
1858 5.9
1859 5.9
1860 5.9
1861 5.9
1862 5.9
1863 5.9
1864 5.9
1865 5.9
1866 5.9
1867 5.9
1868 5.9
1869 5.9
1870 5.9
1871 5.9
1872 5.9
1873 5.9
1874 5.9
1875 5.9
1876 5.9
1877 5.9
1878 5.9
1879 5.9
1880 5.9
1881 5.9
1882 5.9
1883 5.9
1884 5.9
1885 5.9
1886 5.9
1887 5.9
1888 5.9
1889 5.9
1890 5.9
1891 5.9
1892 5.9
1893 5.9
1894 5.9
1895 5.9
1896 5.9
1897 5.9
1898 5.9
1899 5.9
1900 5.9
1901 5.9
1902 5.9
1903 5.9
1904 5.9
1905 5.9
1906 5.9
1907 5.9
1908 5.9
1909 5.9
1910 5.9
1911 5.9
1912 5.9
1913 5.9
1914 5.9
1915 5.9
1916 5.9
1917 5.9
1918 5.9
1919 5.9
1920 5.9
1921 5.9
1922 5.9
1923 5.9
1924 5.9
1925 5.9
1926 5.82
1927 5.75
1928 5.67
1929 5.59
1930 5.52
1931 5.44
1932 5.36
1933 5.28
1934 5.21
1935 5.13
1936 5.05
1937 4.98
1938 4.9
1939 4.82
1940 4.75
1941 4.67
1942 4.59
1943 4.52
1944 4.44
1945 4.36
1946 4.29
1947 4.21
1948 4.13
1949 4.05
1950 3.98
1951 3.99
1952 4.02
1953 4.06
1954 4.12
1955 4.18
1956 4.25
1957 4.32
1958 4.4
1959 4.46
1960 4.5
1961 4.5
1962 4.45
1963 4.36
1964 4.22
1965 4.06
1966 3.89
1967 3.75
1968 3.64
1969 3.57
1970 3.53
1971 3.5
1972 3.47
1973 3.41
1974 3.33
1975 3.23
1976 3.14
1977 3.06
1978 3.01
1979 2.99
1980 2.99
1981 2.99
1982 2.99
1983 2.97
1984 2.92
1985 2.86
1986 2.79
1987 2.73
1988 2.68
1989 2.65
1990 2.64
1991 2.63
1992 2.62
1993 2.6
1994 2.57
1995 2.51
1996 2.44
1997 2.36
1998 2.26
1999 2.17
2000 2.07
2001 1.99
2002 1.93
2003 1.89
2004 1.86
2005 1.86
2006 1.87
2007 1.87
2008 1.88
2009 1.88
2010 1.87
2011 1.85
2012 1.83
2013 1.81
2014 1.79
2015 1.78
2016 1.77
2017 1.76
2018 1.75