Year Total
1800 6.3
1801 6.3
1802 6.3
1803 6.3
1804 6.3
1805 6.3
1806 6.3
1807 6.3
1808 6.3
1809 6.3
1810 6.3
1811 6.3
1812 6.3
1813 6.3
1814 6.3
1815 6.3
1816 6.3
1817 6.3
1818 6.3
1819 6.3
1820 6.3
1821 6.3
1822 6.3
1823 6.3
1824 6.3
1825 6.3
1826 6.3
1827 6.3
1828 6.3
1829 6.3
1830 6.3
1831 6.3
1832 6.3
1833 6.3
1834 6.3
1835 6.3
1836 6.3
1837 6.3
1838 6.3
1839 6.3
1840 6.3
1841 6.3
1842 6.3
1843 6.3
1844 6.3
1845 6.3
1846 6.3
1847 6.3
1848 6.3
1849 6.3
1850 6.3
1851 6.3
1852 6.3
1853 6.3
1854 6.3
1855 6.3
1856 6.3
1857 6.3
1858 6.3
1859 6.3
1860 6.3
1861 6.3
1862 6.3
1863 6.3
1864 6.3
1865 6.3
1866 6.3
1867 6.3
1868 6.3
1869 6.3
1870 6.3
1871 6.3
1872 6.3
1873 6.3
1874 6.3
1875 6.3
1876 6.3
1877 6.3
1878 6.3
1879 6.3
1880 6.3
1881 6.3
1882 6.3
1883 6.3
1884 6.3
1885 6.3
1886 6.3
1887 6.3
1888 6.3
1889 6.3
1890 6.3
1891 6.3
1892 6.3
1893 6.3
1894 6.3
1895 6.3
1896 6.3
1897 6.3
1898 6.3
1899 6.3
1900 6.3
1901 6.3
1902 6.3
1903 6.3
1904 6.3
1905 6.3
1906 6.3
1907 6.3
1908 6.3
1909 6.3
1910 6.3
1911 6.3
1912 6.3
1913 6.3
1914 6.3
1915 6.3
1916 6.3
1917 6.3
1918 6.3
1919 6.3
1920 6.3
1921 6.3
1922 6.3
1923 6.3
1924 6.3
1925 6.3
1926 6.3
1927 6.3
1928 6.3
1929 6.3
1930 6.3
1931 6.3
1932 6.3
1933 6.3
1934 6.3
1935 6.3
1936 6.3
1937 6.3
1938 6.3
1939 6.3
1940 6.3
1941 6.3
1942 6.3
1943 6.3
1944 6.3
1945 6.3
1946 6.3
1947 6.3
1948 6.3
1949 6.3
1950 6.3
1951 6.3
1952 6.31
1953 6.31
1954 6.32
1955 6.34
1956 6.35
1957 6.38
1958 6.4
1959 6.43
1960 6.46
1961 6.49
1962 6.53
1963 6.56
1964 6.6
1965 6.63
1966 6.67
1967 6.7
1968 6.74
1969 6.77
1970 6.8
1971 6.83
1972 6.84
1973 6.83
1974 6.82
1975 6.78
1976 6.73
1977 6.67
1978 6.6
1979 6.52
1980 6.44
1981 6.37
1982 6.32
1983 6.27
1984 6.24
1985 6.22
1986 6.21
1987 6.19
1988 6.17
1989 6.14
1990 6.09
1991 6
1992 5.88
1993 5.73
1994 5.55
1995 5.35
1996 5.15
1997 4.96
1998 4.78
1999 4.62
2000 4.48
2001 4.36
2002 4.24
2003 4.12
2004 3.99
2005 3.87
2006 3.74
2007 3.62
2008 3.5
2009 3.4
2010 3.3
2011 3.21
2012 3.13
2013 3.06
2014 2.98
2015 2.91
2016 2.85
2017 2.79
2018 2.73