Year Total
1800 6.4
1801 6.4
1802 6.4
1803 6.4
1804 6.4
1805 6.4
1806 6.4
1807 6.4
1808 6.4
1809 6.4
1810 6.4
1811 6.4
1812 6.4
1813 6.4
1814 6.4
1815 6.4
1816 6.4
1817 6.4
1818 6.4
1819 6.4
1820 6.4
1821 6.4
1822 6.4
1823 6.4
1824 6.4
1825 6.4
1826 6.4
1827 6.4
1828 6.4
1829 6.4
1830 6.4
1831 6.4
1832 6.4
1833 6.4
1834 6.4
1835 6.4
1836 6.4
1837 6.4
1838 6.4
1839 6.4
1840 6.4
1841 6.4
1842 6.4
1843 6.4
1844 6.4
1845 6.4
1846 6.4
1847 6.4
1848 6.4
1849 6.4
1850 6.4
1851 6.4
1852 6.4
1853 6.4
1854 6.4
1855 6.4
1856 6.4
1857 6.4
1858 6.4
1859 6.4
1860 6.4
1861 6.4
1862 6.4
1863 6.4
1864 6.4
1865 6.4
1866 6.4
1867 6.4
1868 6.4
1869 6.4
1870 6.4
1871 6.4
1872 6.4
1873 6.4
1874 6.4
1875 6.4
1876 6.4
1877 6.4
1878 6.4
1879 6.4
1880 6.4
1881 6.4
1882 6.4
1883 6.4
1884 6.4
1885 6.4
1886 6.4
1887 6.4
1888 6.4
1889 6.4
1890 6.4
1891 6.4
1892 6.4
1893 6.4
1894 6.4
1895 6.4
1896 6.4
1897 6.4
1898 6.4
1899 6.4
1900 6.4
1901 6.4
1902 6.4
1903 6.4
1904 6.4
1905 6.4
1906 6.4
1907 6.4
1908 6.4
1909 6.4
1910 6.4
1911 6.4
1912 6.4
1913 6.4
1914 6.4
1915 6.4
1916 6.4
1917 6.4
1918 6.4
1919 6.4
1920 6.4
1921 6.4
1922 6.4
1923 6.4
1924 6.4
1925 6.4
1926 6.4
1927 6.4
1928 6.4
1929 6.4
1930 6.4
1931 6.38
1932 6.35
1933 6.32
1934 6.3
1935 6.27
1936 6.24
1937 6.22
1938 6.19
1939 6.16
1940 6.13
1941 6.11
1942 6.08
1943 6.05
1944 6.02
1945 5.99
1946 5.96
1947 5.44
1948 4.88
1949 5.77
1950 6.66
1951 6.66
1952 6.68
1953 6.7
1954 6.73
1955 6.77
1956 6.81
1957 6.85
1958 6.88
1959 6.92
1960 6.94
1961 6.97
1962 6.99
1963 7.01
1964 7.02
1965 7.01
1966 6.98
1967 6.94
1968 6.88
1969 6.8
1970 6.71
1971 6.59
1972 6.47
1973 6.33
1974 6.19
1975 6.04
1976 5.89
1977 5.73
1978 5.57
1979 5.41
1980 5.24
1981 5.08
1982 4.92
1983 4.75
1984 4.59
1985 4.43
1986 4.25
1987 4.07
1988 3.88
1989 3.68
1990 3.48
1991 3.28
1992 3.09
1993 2.91
1994 2.75
1995 2.61
1996 2.49
1997 2.38
1998 2.29
1999 2.21
2000 2.14
2001 2.09
2002 2.05
2003 2.02
2004 2
2005 1.99
2006 2
2007 2.02
2008 2.06
2009 2.1
2010 2.14
2011 2.18
2012 2.21
2013 2.23
2014 2.23
2015 2.22
2016 2.2
2017 2.18
2018 2.15