Year Total
1800 5.9
1801 5.9
1802 5.9
1803 5.9
1804 5.9
1805 5.9
1806 5.9
1807 5.9
1808 5.9
1809 5.9
1810 5.9
1811 5.9
1812 5.9
1813 5.9
1814 5.9
1815 5.9
1816 5.9
1817 5.9
1818 5.9
1819 5.9
1820 5.9
1821 5.9
1822 5.9
1823 5.9
1824 5.9
1825 5.9
1826 5.9
1827 5.9
1828 5.9
1829 5.9
1830 5.9
1831 5.9
1832 5.9
1833 5.9
1834 5.9
1835 5.9
1836 5.9
1837 5.9
1838 5.9
1839 5.9
1840 5.9
1841 5.9
1842 5.9
1843 5.9
1844 5.9
1845 5.9
1846 5.9
1847 5.9
1848 5.9
1849 5.9
1850 5.9
1851 5.86
1852 5.82
1853 5.78
1854 5.74
1855 5.7
1856 5.66
1857 5.62
1858 5.58
1859 5.55
1860 5.51
1861 5.47
1862 5.43
1863 5.7
1864 5.96
1865 5.97
1866 5.98
1867 5.98
1868 5.99
1869 6
1870 6
1871 5.95
1872 5.89
1873 5.84
1874 5.78
1875 5.73
1876 5.67
1877 5.62
1878 5.56
1879 5.51
1880 5.45
1881 5.45
1882 5.44
1883 5.44
1884 5.43
1885 5.43
1886 5.42
1887 5.42
1888 5.41
1889 5.41
1890 5.4
1891 5.43
1892 5.46
1893 5.48
1894 5.51
1895 5.54
1896 5.57
1897 5.6
1898 5.63
1899 5.65
1900 5.68
1901 5.54
1902 5.41
1903 5.27
1904 5.13
1905 5
1906 5.04
1907 5.09
1908 5.13
1909 5.18
1910 5.23
1911 5.18
1912 5.14
1913 5.1
1914 5.05
1915 5.01
1916 4.96
1917 4.92
1918 4.88
1919 4.83
1920 4.79
1921 4.75
1922 4.7
1923 4.66
1924 4.62
1925 4.57
1926 4.53
1927 4.49
1928 4.44
1929 4.4
1930 4.36
1931 4.31
1932 4.27
1933 4.22
1934 4.18
1935 4.14
1936 4.09
1937 4.05
1938 4.01
1939 3.96
1940 3.92
1941 3.88
1942 3.85
1943 3.81
1944 3.78
1945 3.74
1946 3.71
1947 3.68
1948 3.65
1949 3.62
1950 3.59
1951 3.49
1952 3.29
1953 3.11
1954 2.96
1955 2.82
1956 2.71
1957 2.63
1958 2.56
1959 2.52
1960 2.49
1961 2.49
1962 2.48
1963 2.48
1964 2.48
1965 2.47
1966 2.45
1967 2.44
1968 2.42
1969 2.4
1970 2.39
1971 2.38
1972 2.37
1973 2.36
1974 2.36
1975 2.36
1976 2.37
1977 2.37
1978 2.36
1979 2.36
1980 2.35
1981 2.34
1982 2.33
1983 2.32
1984 2.31
1985 2.29
1986 2.27
1987 2.24
1988 2.2
1989 2.15
1990 2.1
1991 2.05
1992 2
1993 1.95
1994 1.92
1995 1.89
1996 1.86
1997 1.84
1998 1.82
1999 1.79
2000 1.77
2001 1.74
2002 1.72
2003 1.69
2004 1.66
2005 1.64
2006 1.61
2007 1.6
2008 1.58
2009 1.58
2010 1.58
2011 1.58
2012 1.58
2013 1.59
2014 1.6
2015 1.6
2016 1.61
2017 1.62
2018 1.62