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 6.89
1927 6.91
1928 6.92
1929 6.94
1930 6.95
1931 6.97
1932 6.98
1933 7
1934 7.01
1935 7.03
1936 7.04
1937 7.06
1938 7.07
1939 7.09
1940 7.1
1941 7.12
1942 7.13
1943 7.15
1944 7.16
1945 7.18
1946 7.19
1947 7.21
1948 7.22
1949 7.24
1950 7.25
1951 7.25
1952 7.25
1953 7.25
1954 7.25
1955 7.25
1956 7.25
1957 7.25
1958 7.25
1959 7.25
1960 7.25
1961 7.25
1962 7.25
1963 7.26
1964 7.26
1965 7.27
1966 7.28
1967 7.28
1968 7.29
1969 7.29
1970 7.31
1971 7.35
1972 7.41
1973 7.5
1974 7.62
1975 7.75
1976 7.89
1977 8.02
1978 8.14
1979 8.23
1980 8.3
1981 8.34
1982 8.35
1983 8.34
1984 8.3
1985 8.22
1986 8.1
1987 7.93
1988 7.72
1989 7.46
1990 7.17
1991 6.83
1992 6.47
1993 6.1
1994 5.72
1995 5.35
1996 4.98
1997 4.63
1998 4.3
1999 3.99
2000 3.72
2001 3.48
2002 3.29
2003 3.14
2004 3.03
2005 2.95
2006 2.91
2007 2.89
2008 2.89
2009 2.9
2010 2.9
2011 2.9
2012 2.88
2013 2.85
2014 2.8
2015 2.74
2016 2.67
2017 2.59
2018 2.52