Year Years
1800 38.37
1801 38.37
1802 38.37
1803 38.37
1804 38.37
1805 38.37
1806 38.37
1807 38.37
1808 38.37
1809 38.37
1810 38.37
1811 38.37
1812 38.37
1813 38.37
1814 38.37
1815 38.37
1816 38.37
1817 38.37
1818 38.37
1819 38.37
1820 38.37
1821 38.37
1822 38.37
1823 38.37
1824 38.37
1825 38.37
1826 38.37
1827 38.37
1828 38.37
1829 38.37
1830 38.37
1831 38.37
1832 38.37
1833 38.37
1834 38.37
1835 38.37
1836 38.37
1837 38.37
1838 38.37
1839 38.37
1840 38.37
1841 38.37
1842 38.37
1843 38.37
1844 38.37
1845 38.37
1846 38.37
1847 38.37
1848 38.37
1849 38.37
1850 38.37
1851 38.37
1852 38.37
1853 38.37
1854 38.37
1855 38.37
1856 38.37
1857 38.37
1858 38.37
1859 38.37
1860 38.37
1861 38.37
1862 38.37
1863 38.37
1864 38.37
1865 38.37
1866 38.37
1867 38.37
1868 38.37
1869 38.37
1870 38.37
1871 38.37
1872 38.37
1873 38.37
1874 38.37
1875 38.37
1876 38.48
1877 38.58
1878 38.69
1879 38.8
1880 38.9
1881 39
1882 39.11
1883 39.22
1884 39.32
1885 39.43
1886 39.72
1887 40.02
1888 40.31
1889 40.61
1890 40.9
1891 41.19
1892 41.49
1893 41.78
1894 42.08
1895 42.37
1896 42.68
1897 42.97
1898 43.28
1899 43.59
1900 43.9
1901 44.2
1902 44.51
1903 44.82
1904 45.12
1905 45.43
1906 46.02
1907 46.61
1908 47.21
1909 47.8
1910 48.38
1911 48.97
1912 49.56
1913 50.15
1914 46.15
1915 40.51
1916 38.97
1917 40.06
1918 32.92
1919 48.29
1920 53.47
1921 54.97
1922 55.58
1923 56.18
1924 56.78
1925 57.38
1926 57.79
1927 58.2
1928 58.6
1929 59
1930 59.41
1931 59.82
1932 60.23
1933 60.63
1934 61.04
1935 61.45
1936 61.74
1937 62.02
1938 62.3
1939 60.95
1940 60.6
1941 58.95
1942 54.95
1943 49.65
1944 36.96
1945 28.97
1946 60.45
1947 62.05
1948 63.65
1949 65.24
1950 66.83
1951 67
1952 67.32
1953 67.62
1954 67.92
1955 68.19
1956 68.48
1957 68.4
1958 69.14
1959 69.25
1960 69.17
1961 69.76
1962 69.92
1963 70.01
1964 70.56
1965 70.54
1966 70.66
1967 70.88
1968 70.53
1969 70.37
1970 70.61
1971 70.68
1972 70.9
1973 71.12
1974 71.34
1975 71.52
1976 71.9
1977 72.29
1978 72.48
1979 72.76
1980 72.96
1981 73.19
1982 73.44
1983 73.71
1984 74.02
1985 74.23
1986 74.45
1987 74.72
1988 74.94
1989 75.15
1990 75.28
1991 75.53
1992 75.83
1993 76.01
1994 76.24
1995 76.49
1996 76.74
1997 77.03
1998 77.31
1999 77.59
2000 77.89
2001 78.17
2002 78.4
2003 78.61
2004 78.91
2005 79.15
2006 79.4
2007 79.59
2008 79.76
2009 79.91
2010 80.09
2011 80.27
2012 80.43
2013 80.54
2014 80.76
2015 80.84
2016 80.91
2017 81.08
2018 81.25