Year Total
1800 6.5
1801 6.48
1802 6.46
1803 6.44
1804 6.42
1805 6.4
1806 6.38
1807 6.36
1808 6.34
1809 6.32
1810 6.3
1811 6.28
1812 6.26
1813 6.24
1814 6.22
1815 6.2
1816 6.18
1817 6.16
1818 6.14
1819 6.12
1820 6.1
1821 6.08
1822 6.06
1823 6.04
1824 6.02
1825 6
1826 5.96
1827 5.92
1828 5.87
1829 5.83
1830 5.79
1831 5.75
1832 5.7
1833 5.66
1834 5.62
1835 5.58
1836 5.54
1837 5.49
1838 5.45
1839 5.41
1840 5.37
1841 5.32
1842 5.28
1843 5.24
1844 5.2
1845 5.16
1846 5.11
1847 5.07
1848 5.03
1849 4.99
1850 4.94
1851 5.01
1852 4.7
1853 5.03
1854 4.86
1855 5.32
1856 5.19
1857 5.63
1858 5.71
1859 5.75
1860 5.71
1861 5.67
1862 5.8
1863 5.59
1864 5.75
1865 5.64
1866 5.33
1867 5.41
1868 5.43
1869 5.19
1870 5.19
1871 5.09
1872 4.97
1873 5.01
1874 4.93
1875 4.81
1876 4.81
1877 4.69
1878 4.74
1879 4.8
1880 4.73
1881 4.73
1882 4.62
1883 4.66
1884 4.77
1885 4.78
1886 4.74
1887 4.77
1888 4.76
1889 4.65
1890 4.69
1891 4.62
1892 4.52
1893 4.4
1894 4.13
1895 4.07
1896 3.81
1897 3.78
1898 3.64
1899 3.66
1900 3.66
1901 3.64
1902 3.58
1903 3.39
1904 3.54
1905 3.51
1906 3.35
1907 3.35
1908 3.35
1909 3.35
1910 3.35
1911 3.51
1912 3.51
1913 3.51
1914 3.51
1915 3.51
1916 3.07
1917 3.07
1918 3.07
1919 3.07
1920 3.07
1921 3.12
1922 3.11
1923 3.02
1924 2.97
1925 2.95
1926 2.85
1927 2.8
1928 2.77
1929 2.64
1930 2.58
1931 2.36
1932 2.19
1933 2.17
1934 2.11
1935 2.12
1936 2.18
1937 2.21
1938 2.21
1939 2.22
1940 2.26
1941 2.36
1942 2.38
1943 2.57
1944 2.63
1945 2.74
1946 2.99
1947 3.08
1948 2.99
1949 2.99
1950 3.07
1951 3.06
1952 3.18
1953 3.19
1954 3.2
1955 3.28
1956 3.33
1957 3.42
1958 3.42
1959 3.44
1960 3.44
1961 3.52
1962 3.41
1963 3.32
1964 3.16
1965 3
1966 2.92
1967 2.87
1968 2.88
1969 2.86
1970 2.81
1971 2.85
1972 2.68
1973 2.48
1974 2.33
1975 2.18
1976 2.09
1977 2.03
1978 1.97
1979 1.92
1980 1.9
1981 1.92
1982 1.91
1983 1.91
1984 1.86
1985 1.9
1986 1.87
1987 1.86
1988 1.85
1989 1.85
1990 1.88
1991 1.86
1992 1.87
1993 1.85
1994 1.84
1995 1.82
1996 1.81
1997 1.79
1998 1.77
1999 1.76
2000 1.76
2001 1.76
2002 1.78
2003 1.79
2004 1.82
2005 1.86
2006 1.89
2007 1.92
2008 1.94
2009 1.94
2010 1.93
2011 1.92
2012 1.9
2013 1.89
2014 1.87
2015 1.86
2016 1.85
2017 1.84
2018 1.83