Year Total
1800 6.88
1801 6.88
1802 6.88
1803 6.88
1804 6.88
1805 6.88
1806 6.88
1807 6.88
1808 6.88
1809 6.88
1810 6.88
1811 6.88
1812 6.88
1813 6.88
1814 6.88
1815 6.88
1816 6.88
1817 6.88
1818 6.88
1819 6.88
1820 6.88
1821 6.88
1822 6.88
1823 6.88
1824 6.88
1825 6.88
1826 6.88
1827 6.88
1828 6.88
1829 6.88
1830 6.88
1831 6.88
1832 6.88
1833 6.88
1834 6.88
1835 6.88
1836 6.88
1837 6.88
1838 6.88
1839 6.88
1840 6.88
1841 6.88
1842 6.88
1843 6.88
1844 6.88
1845 6.88
1846 6.88
1847 6.88
1848 6.88
1849 6.88
1850 6.88
1851 6.88
1852 6.88
1853 6.88
1854 6.88
1855 6.88
1856 6.88
1857 6.88
1858 6.88
1859 6.88
1860 6.88
1861 6.88
1862 6.88
1863 6.88
1864 6.88
1865 6.88
1866 6.88
1867 6.88
1868 6.88
1869 6.88
1870 6.88
1871 6.88
1872 6.88
1873 6.88
1874 6.88
1875 6.88
1876 6.88
1877 6.88
1878 6.88
1879 6.88
1880 6.88
1881 6.88
1882 6.88
1883 6.88
1884 6.88
1885 6.88
1886 6.88
1887 6.88
1888 6.88
1889 6.88
1890 6.88
1891 6.88
1892 6.88
1893 6.88
1894 6.88
1895 6.88
1896 6.88
1897 6.88
1898 6.88
1899 6.88
1900 6.88
1901 6.88
1902 6.88
1903 6.88
1904 6.88
1905 6.88
1906 6.88
1907 6.88
1908 6.88
1909 6.88
1910 6.88
1911 6.88
1912 6.88
1913 6.88
1914 6.88
1915 6.88
1916 6.88
1917 6.88
1918 6.88
1919 6.88
1920 6.88
1921 6.88
1922 6.88
1923 6.88
1924 6.88
1925 6.88
1926 6.9
1927 6.91
1928 6.93
1929 6.94
1930 6.96
1931 6.98
1932 6.99
1933 7.01
1934 7.02
1935 7.04
1936 7.06
1937 7.08
1938 7.09
1939 7.11
1940 7.13
1941 7.15
1942 7.16
1943 7.18
1944 7.2
1945 7.22
1946 7.24
1947 7.26
1948 7.28
1949 7.3
1950 7.32
1951 7.32
1952 7.31
1953 7.31
1954 7.32
1955 7.33
1956 7.34
1957 7.37
1958 7.4
1959 7.44
1960 7.49
1961 7.53
1962 7.58
1963 7.62
1964 7.67
1965 7.71
1966 7.74
1967 7.76
1968 7.78
1969 7.79
1970 7.81
1971 7.85
1972 7.92
1973 8
1974 8.12
1975 8.24
1976 8.38
1977 8.5
1978 8.61
1979 8.69
1980 8.75
1981 8.8
1982 8.83
1983 8.85
1984 8.86
1985 8.87
1986 8.86
1987 8.83
1988 8.79
1989 8.71
1990 8.61
1991 8.46
1992 8.27
1993 8.05
1994 7.8
1995 7.53
1996 7.25
1997 6.99
1998 6.74
1999 6.51
2000 6.31
2001 6.13
2002 5.95
2003 5.78
2004 5.6
2005 5.43
2006 5.25
2007 5.09
2008 4.94
2009 4.8
2010 4.67
2011 4.55
2012 4.44
2013 4.33
2014 4.22
2015 4.1
2016 4
2017 3.89
2018 3.79