Year Total
1800 6.6
1801 6.6
1802 6.6
1803 6.6
1804 6.6
1805 6.6
1806 6.6
1807 6.6
1808 6.6
1809 6.6
1810 6.6
1811 6.6
1812 6.6
1813 6.6
1814 6.6
1815 6.6
1816 6.6
1817 6.6
1818 6.6
1819 6.6
1820 6.6
1821 6.6
1822 6.6
1823 6.6
1824 6.6
1825 6.6
1826 6.6
1827 6.6
1828 6.6
1829 6.6
1830 6.6
1831 6.6
1832 6.6
1833 6.6
1834 6.6
1835 6.6
1836 6.6
1837 6.6
1838 6.6
1839 6.6
1840 6.6
1841 6.6
1842 6.6
1843 6.6
1844 6.6
1845 6.6
1846 6.6
1847 6.6
1848 6.6
1849 6.6
1850 6.6
1851 6.6
1852 6.6
1853 6.6
1854 6.6
1855 6.6
1856 6.6
1857 6.6
1858 6.6
1859 6.6
1860 6.6
1861 6.6
1862 6.6
1863 6.6
1864 6.6
1865 6.6
1866 6.6
1867 6.6
1868 6.6
1869 6.6
1870 6.6
1871 6.6
1872 6.6
1873 6.6
1874 6.6
1875 6.6
1876 6.6
1877 6.6
1878 6.6
1879 6.6
1880 6.6
1881 6.6
1882 6.6
1883 6.6
1884 6.6
1885 6.6
1886 6.6
1887 6.6
1888 6.6
1889 6.6
1890 6.6
1891 6.6
1892 6.6
1893 6.6
1894 6.6
1895 6.6
1896 6.6
1897 6.6
1898 6.6
1899 6.6
1900 6.6
1901 6.6
1902 6.6
1903 6.6
1904 6.6
1905 6.6
1906 6.6
1907 6.6
1908 6.6
1909 6.6
1910 6.6
1911 6.6
1912 6.6
1913 6.6
1914 6.6
1915 6.6
1916 6.6
1917 6.6
1918 6.6
1919 6.6
1920 6.6
1921 6.6
1922 6.6
1923 6.6
1924 6.6
1925 6.6
1926 6.64
1927 6.69
1928 6.73
1929 6.77
1930 6.82
1931 6.86
1932 6.9
1933 6.95
1934 6.99
1935 7.03
1936 7.08
1937 7.12
1938 7.16
1939 7.21
1940 7.25
1941 7.29
1942 7.34
1943 7.38
1944 7.42
1945 7.47
1946 7.51
1947 7.55
1948 7.6
1949 7.64
1950 7.68
1951 7.66
1952 7.62
1953 7.58
1954 7.54
1955 7.49
1956 7.44
1957 7.39
1958 7.33
1959 7.27
1960 7.2
1961 7.12
1962 7.03
1963 6.94
1964 6.84
1965 6.73
1966 6.63
1967 6.53
1968 6.43
1969 6.35
1970 6.27
1971 6.2
1972 6.13
1973 6.07
1974 6
1975 5.93
1976 5.86
1977 5.79
1978 5.72
1979 5.65
1980 5.58
1981 5.5
1982 5.43
1983 5.36
1984 5.28
1985 5.21
1986 5.14
1987 5.08
1988 5.02
1989 4.97
1990 4.93
1991 4.89
1992 4.85
1993 4.81
1994 4.78
1995 4.73
1996 4.68
1997 4.61
1998 4.54
1999 4.46
2000 4.37
2001 4.27
2002 4.16
2003 4.06
2004 3.95
2005 3.85
2006 3.76
2007 3.68
2008 3.61
2009 3.55
2010 3.5
2011 3.46
2012 3.42
2013 3.38
2014 3.35
2015 3.31
2016 3.28
2017 3.24
2018 3.2