Year Years
1800 36.6
1801 36.6
1802 36.6
1803 36.6
1804 36.6
1805 36.6
1806 36.6
1807 36.6
1808 36.6
1809 36.6
1810 36.6
1811 36.6
1812 36.6
1813 36.6
1814 36.6
1815 36.6
1816 36.6
1817 36.6
1818 36.6
1819 36.6
1820 36.6
1821 36.6
1822 36.6
1823 36.6
1824 36.6
1825 36.6
1826 36.6
1827 36.6
1828 36.6
1829 36.6
1830 36.6
1831 36.6
1832 36.6
1833 36.6
1834 36.6
1835 36.6
1836 36.6
1837 36.6
1838 36.6
1839 36.6
1840 36.6
1841 36.6
1842 36.6
1843 36.6
1844 36.6
1845 36.6
1846 36.6
1847 36.6
1848 36.6
1849 36.6
1850 36.6
1851 36.6
1852 36.6
1853 36.6
1854 36.6
1855 36.6
1856 36.6
1857 36.6
1858 36.6
1859 36.6
1860 36.6
1861 36.6
1862 36.6
1863 36.6
1864 36.6
1865 36.6
1866 36.6
1867 36.6
1868 36.6
1869 36.6
1870 36.6
1871 36.59
1872 36.59
1873 36.58
1874 36.57
1875 36.56
1876 36.56
1877 36.55
1878 36.54
1879 36.53
1880 36.53
1881 36.52
1882 36.51
1883 36.5
1884 36.5
1885 36.49
1886 36.48
1887 36.47
1888 36.47
1889 36.46
1890 36.45
1891 36.44
1892 36.44
1893 36.43
1894 36.42
1895 36.42
1896 36.41
1897 36.4
1898 36.39
1899 36.39
1900 36.38
1901 36.37
1902 36.36
1903 36.36
1904 36.35
1905 36.34
1906 36.33
1907 36.33
1908 36.32
1909 36.31
1910 36.3
1911 36.3
1912 36.29
1913 36.28
1914 36.27
1915 36.27
1916 36.26
1917 36.25
1918 19.9
1919 36.24
1920 36.23
1921 37.14
1922 38.06
1923 38.97
1924 39.87
1925 40.78
1926 41.69
1927 42.6
1928 43.51
1929 44.42
1930 45.32
1931 46.23
1932 47.14
1933 48.05
1934 48.96
1935 49.87
1936 50.76
1937 51.67
1938 52.58
1939 53.48
1940 54.39
1941 51.45
1942 49.69
1943 48.05
1944 46.62
1945 48.35
1946 54.16
1947 60.05
1948 61.52
1949 62.5
1950 63.41
1951 63.69
1952 64.24
1953 64.77
1954 65.25
1955 65.71
1956 66.13
1957 66.52
1958 66.87
1959 67.17
1960 67.43
1961 67.62
1962 67.77
1963 67.85
1964 67.89
1965 67.89
1966 67.88
1967 67.87
1968 67.89
1969 67.93
1970 68.02
1971 68.29
1972 68.55
1973 68.81
1974 69.08
1975 69.33
1976 69.57
1977 69.8
1978 70.04
1979 70.28
1980 70.48
1981 70.65
1982 70.8
1983 70.86
1984 71.2
1985 71.69
1986 72.1
1987 72.2
1988 72.76
1989 73.08
1990 73.54
1991 73.49
1992 73.68
1993 73.72
1994 74.04
1995 74.47
1996 74.79
1997 75.02
1998 75.24
1999 75.53
2000 75.94
2001 76.19
2002 76.52
2003 76.71
2004 77.1
2005 77.5
2006 77.87
2007 78.23
2008 78.72
2009 79.08
2010 79.45
2011 79.81
2012 80.01
2013 80.26
2014 80.74
2015 80.7
2016 80.82
2017 80.97
2018 81.12