Year Years 1800 35.7 1801 35.7 1802 35.7 1803 35.7 1804 35.7 1805 35.7 1806 35.7 1807 35.7 1808 35.7 1809 35.7 1810 35.7 1811 35.7 1812 35.7 1813 35.7 1814 35.7 1815 35.7 1816 35.7 1817 35.7 1818 35.7 1819 35.7 1820 35.7 1821 35.7 1822 35.7 1823 35.7 1824 35.7 1825 35.7 1826 35.7 1827 35.7 1828 35.7 1829 35.7 1830 35.7 1831 35.7 1832 35.7 1833 35.7 1834 35.7 1835 35.7 1836 35.7 1837 35.7 1838 35.7 1839 35.7 1840 35.7 1841 35.7 1842 35.7 1843 35.7 1844 35.7 1845 35.7 1846 35.7 1847 35.7 1848 35.7 1849 35.7 1850 35.7 1851 35.7 1852 35.7 1853 35.7 1854 35.7 1855 35.7 1856 35.7 1857 35.7 1858 35.7 1859 35.7 1860 35.7 1861 35.7 1862 35.7 1863 35.7 1864 35.7 1865 35.7 1866 35.7 1867 35.7 1868 35.7 1869 35.7 1870 35.7 1871 35.7 1872 35.7 1873 35.7 1874 35.71 1875 35.71 1876 35.71 1877 35.71 1878 35.71 1879 35.71 1880 35.71 1881 35.71 1882 35.72 1883 35.72 1884 35.72 1885 35.72 1886 35.72 1887 35.72 1888 35.72 1889 35.72 1890 35.73 1891 35.73 1892 35.73 1893 35.73 1894 35.73 1895 35.73 1896 35.73 1897 35.74 1898 35.74 1899 35.74 1900 35.74 1901 35.74 1902 35.74 1903 35.74 1904 35.74 1905 35.75 1906 35.75 1907 35.75 1908 35.75 1909 35.75 1910 35.75 1911 35.75 1912 35.76 1913 35.76 1914 35.76 1915 35.76 1916 35.76 1917 35.76 1918 26.5 1919 35.76 1920 35.77 1921 36.3 1922 36.82 1923 37.35 1924 37.87 1925 38.41 1926 38.94 1927 39.46 1928 40 1929 40.52 1930 41.05 1931 41.57 1932 42.11 1933 43.17 1934 44.23 1935 45.3 1936 46.36 1937 47.44 1938 48.5 1939 49.57 1940 50.63 1941 45.52 1942 44.82 1943 42.51 1944 41.31 1945 45.53 1946 54.15 1947 58.09 1948 59.16 1949 60.22 1950 61.29 1951 61.21 1952 61.14 1953 61.26 1954 61.53 1955 61.98 1956 62.59 1957 63.33 1958 64.18 1959 65.07 1960 65.95 1961 66.72 1962 67.34 1963 67.75 1964 67.96 1965 68.02 1966 67.98 1967 67.94 1968 67.99 1969 68.14 1970 68.38 1971 68.95 1972 69.23 1973 69.37 1974 69.91 1975 70.06 1976 70.43 1977 69.77 1978 69.88 1979 69.52 1980 69.67 1981 69.77 1982 70.05 1983 70.17 1984 70.14 1985 69.85 1986 70.01 1987 69.42 1988 69.76 1989 69.92 1990 69.9 1991 70.37 1992 69.93 1993 69.74 1994 69.48 1995 69.43 1996 69.2 1997 69.39 1998 70.07 1999 70.86 2000 71.19 2001 71.13 2002 71.29 2003 71.61 2004 72.07 2005 72.41 2006 72.84 2007 73.23 2008 73.17 2009 73.33 2010 73.66 2011 74.47 2012 74.58 2013 74.77 2014 74.79 2015 75.12 2016 75.27 2017 75.4 2018 75.53