Year Total
1800 6.28
1801 6.26
1802 6.25
1803 6.23
1804 6.22
1805 6.2
1806 6.19
1807 6.17
1808 6.16
1809 6.14
1810 6.12
1811 6.11
1812 6.09
1813 6.08
1814 6.06
1815 6.05
1816 6.03
1817 6.03
1818 6.16
1819 6.3
1820 6.03
1821 6.3
1822 6.03
1823 5.76
1824 5.49
1825 6.83
1826 6.16
1827 6.3
1828 6.22
1829 6.14
1830 6.06
1831 5.98
1832 5.9
1833 6.43
1834 6.83
1835 5.9
1836 6.3
1837 6.57
1838 6.03
1839 6.43
1840 6.57
1841 6.16
1842 6.43
1843 6.3
1844 6.03
1845 5.36
1846 5.49
1847 5.09
1848 4.82
1849 5.49
1850 5.63
1851 5.63
1852 5.49
1853 5.63
1854 5.36
1855 4.82
1856 5.36
1857 5.76
1858 6.3
1859 6.57
1860 6.57
1861 6.43
1862 6.97
1863 6.57
1864 6.2
1865 5.83
1866 5.46
1867 5.09
1868 5.63
1869 5.63
1870 6.16
1871 5.76
1872 5.49
1873 5.76
1874 5.76
1875 5.49
1876 5.49
1877 5.23
1878 5.23
1879 5.36
1880 5.23
1881 5.09
1882 5.23
1883 5.23
1884 5.09
1885 5.36
1886 5.36
1887 5.36
1888 5.49
1889 5.76
1890 5.63
1891 5.63
1892 5.36
1893 5.63
1894 5.9
1895 5.9
1896 5.76
1897 5.63
1898 5.49
1899 5.49
1900 5.49
1901 5.36
1902 5.36
1903 5.09
1904 5.09
1905 4.96
1906 5.09
1907 5.09
1908 4.96
1909 4.96
1910 4.82
1911 4.69
1912 4.56
1913 4.69
1914 4.82
1915 3.89
1916 3.62
1917 3.22
1918 3.22
1919 4.42
1920 4.69
1921 4.4
1922 4.73
1923 4.82
1924 4.69
1925 4.74
1926 4.44
1927 4.23
1928 4.29
1929 4.26
1930 4.33
1931 4.05
1932 3.87
1933 3.55
1934 3.56
1935 3.49
1936 3.51
1937 3.33
1938 3.25
1939 3.22
1940 3.19
1941 3.16
1942 3.14
1943 3.11
1944 3.08
1945 3.05
1946 3.02
1947 3.47
1948 3.87
1949 3.88
1950 3.6
1951 3.62
1952 3.64
1953 3.65
1954 3.64
1955 3.6
1956 3.55
1957 3.47
1958 3.37
1959 3.25
1960 3.11
1961 2.96
1962 2.82
1963 2.69
1964 2.57
1965 2.48
1966 2.41
1967 2.35
1968 2.31
1969 2.28
1970 2.25
1971 2.24
1972 2.23
1973 2.22
1974 2.22
1975 2.22
1976 2.22
1977 2.23
1978 2.25
1979 2.27
1980 2.28
1981 2.3
1982 2.3
1983 2.3
1984 2.28
1985 2.26
1986 2.23
1987 2.2
1988 2.16
1989 2.12
1990 2.08
1991 2.03
1992 1.97
1993 1.9
1994 1.82
1995 1.73
1996 1.65
1997 1.56
1998 1.48
1999 1.41
2000 1.35
2001 1.31
2002 1.28
2003 1.28
2004 1.28
2005 1.3
2006 1.32
2007 1.34
2008 1.36
2009 1.37
2010 1.37
2011 1.36
2012 1.34
2013 1.33
2014 1.32
2015 1.31
2016 1.3
2017 1.29
2018 1.29