Year Total
1800 8.1
1801 8.1
1802 8.1
1803 8.1
1804 8.1
1805 8.1
1806 8.1
1807 8.1
1808 8.1
1809 8.1
1810 8.1
1811 8.1
1812 8.1
1813 8.1
1814 8.1
1815 8.1
1816 8.1
1817 8.1
1818 8.1
1819 8.1
1820 8.1
1821 8.1
1822 8.1
1823 8.1
1824 8.1
1825 8.1
1826 8.1
1827 8.1
1828 8.1
1829 8.1
1830 8.1
1831 8.1
1832 8.1
1833 8.1
1834 8.1
1835 8.1
1836 8.1
1837 8.1
1838 8.1
1839 8.1
1840 8.1
1841 8.1
1842 8.1
1843 8.1
1844 8.1
1845 8.1
1846 8.1
1847 8.1
1848 8.1
1849 8.1
1850 8.1
1851 8.1
1852 8.1
1853 8.1
1854 8.1
1855 8.1
1856 8.1
1857 8.1
1858 8.1
1859 8.1
1860 8.1
1861 8.1
1862 8.1
1863 8.1
1864 8.1
1865 8.1
1866 8.1
1867 8.1
1868 8.1
1869 8.1
1870 8.1
1871 8.1
1872 8.1
1873 8.1
1874 8.1
1875 8.1
1876 8.1
1877 8.1
1878 8.1
1879 8.1
1880 8.1
1881 8.1
1882 8.1
1883 8.1
1884 8.1
1885 8.1
1886 8.1
1887 8.1
1888 8.1
1889 8.1
1890 8.1
1891 8.1
1892 8.1
1893 8.1
1894 8.1
1895 8.1
1896 8.07
1897 8.04
1898 8.01
1899 7.98
1900 7.95
1901 7.92
1902 7.89
1903 7.86
1904 7.83
1905 7.8
1906 7.77
1907 7.74
1908 7.71
1909 7.68
1910 7.65
1911 7.62
1912 7.59
1913 7.56
1914 7.53
1915 7.5
1916 7.47
1917 7.44
1918 7.41
1919 7.38
1920 7.35
1921 7.32
1922 7.29
1923 7.26
1924 7.23
1925 7.2
1926 7.14
1927 7.08
1928 7.01
1929 6.95
1930 6.89
1931 6.82
1932 6.75
1933 6.68
1934 6.6
1935 6.52
1936 6.44
1937 6.36
1938 6.28
1939 6.19
1940 6.11
1941 6.02
1942 5.93
1943 5.84
1944 5.75
1945 5.66
1946 5.58
1947 5.5
1948 5.42
1949 5.34
1950 5.26
1951 5.25
1952 5.25
1953 5.28
1954 5.32
1955 5.39
1956 5.48
1957 5.58
1958 5.68
1959 5.79
1960 5.88
1961 5.94
1962 5.96
1963 5.95
1964 5.89
1965 5.79
1966 5.66
1967 5.51
1968 5.35
1969 5.19
1970 5.02
1971 4.85
1972 4.68
1973 4.51
1974 4.34
1975 4.18
1976 4.02
1977 3.87
1978 3.73
1979 3.61
1980 3.5
1981 3.41
1982 3.34
1983 3.29
1984 3.26
1985 3.24
1986 3.22
1987 3.2
1988 3.18
1989 3.14
1990 3.09
1991 3.02
1992 2.93
1993 2.82
1994 2.71
1995 2.58
1996 2.45
1997 2.33
1998 2.21
1999 2.11
2000 2.03
2001 1.96
2002 1.91
2003 1.87
2004 1.84
2005 1.82
2006 1.82
2007 1.84
2008 1.87
2009 1.91
2010 1.96
2011 2.01
2012 2.05
2013 2.08
2014 2.09
2015 2.09
2016 2.08
2017 2.06
2018 2.04