Year Total
1800 6.51
1801 6.51
1802 6.51
1803 6.51
1804 6.51
1805 6.51
1806 6.51
1807 6.51
1808 6.51
1809 6.51
1810 6.51
1811 6.51
1812 6.51
1813 6.51
1814 6.51
1815 6.51
1816 6.51
1817 6.51
1818 6.51
1819 6.51
1820 6.51
1821 6.51
1822 6.51
1823 6.51
1824 6.51
1825 6.51
1826 6.51
1827 6.51
1828 6.51
1829 6.51
1830 6.51
1831 6.51
1832 6.51
1833 6.51
1834 6.51
1835 6.51
1836 6.51
1837 6.51
1838 6.51
1839 6.51
1840 6.51
1841 6.51
1842 6.51
1843 6.51
1844 6.51
1845 6.51
1846 6.51
1847 6.51
1848 6.51
1849 6.51
1850 6.51
1851 6.51
1852 6.51
1853 6.51
1854 6.51
1855 6.51
1856 6.51
1857 6.51
1858 6.51
1859 6.51
1860 6.51
1861 6.51
1862 6.51
1863 6.51
1864 6.51
1865 6.51
1866 6.51
1867 6.51
1868 6.51
1869 6.51
1870 6.51
1871 6.51
1872 6.51
1873 6.51
1874 6.51
1875 6.51
1876 6.51
1877 6.51
1878 6.51
1879 6.51
1880 6.51
1881 6.51
1882 6.51
1883 6.51
1884 6.51
1885 6.51
1886 6.51
1887 6.51
1888 6.51
1889 6.51
1890 6.51
1891 6.51
1892 6.51
1893 6.51
1894 6.51
1895 6.51
1896 6.51
1897 6.51
1898 6.51
1899 6.51
1900 6.51
1901 6.51
1902 6.51
1903 6.51
1904 6.51
1905 6.51
1906 6.51
1907 6.51
1908 6.51
1909 6.51
1910 6.51
1911 6.51
1912 6.51
1913 6.51
1914 6.51
1915 6.51
1916 6.51
1917 6.51
1918 6.51
1919 6.51
1920 6.51
1921 6.51
1922 6.51
1923 6.51
1924 6.51
1925 6.51
1926 6.54
1927 6.57
1928 6.6
1929 6.64
1930 6.67
1931 6.7
1932 6.74
1933 6.77
1934 6.8
1935 6.83
1936 6.87
1937 6.9
1938 6.93
1939 6.97
1940 7
1941 7.03
1942 7.06
1943 7.1
1944 7.13
1945 7.16
1946 7.2
1947 7.23
1948 7.26
1949 7.29
1950 7.33
1951 7.32
1952 7.3
1953 7.29
1954 7.29
1955 7.29
1956 7.31
1957 7.33
1958 7.35
1959 7.36
1960 7.36
1961 7.35
1962 7.3
1963 7.23
1964 7.12
1965 6.97
1966 6.8
1967 6.59
1968 6.37
1969 6.15
1970 5.94
1971 5.76
1972 5.62
1973 5.51
1974 5.45
1975 5.43
1976 5.44
1977 5.47
1978 5.51
1979 5.54
1980 5.55
1981 5.53
1982 5.48
1983 5.39
1984 5.27
1985 5.13
1986 4.99
1987 4.86
1988 4.76
1989 4.69
1990 4.64
1991 4.61
1992 4.58
1993 4.55
1994 4.5
1995 4.45
1996 4.39
1997 4.34
1998 4.3
1999 4.27
2000 4.25
2001 4.24
2002 4.22
2003 4.2
2004 4.18
2005 4.14
2006 4.1
2007 4.06
2008 4.01
2009 3.96
2010 3.91
2011 3.86
2012 3.82
2013 3.77
2014 3.72
2015 3.68
2016 3.64
2017 3.6
2018 3.56