Year Years 1800 431.8 1801 431.8 1802 431.8 1803 431.8 1804 431.8 1805 431.8 1806 431.8 1807 431.8 1808 431.8 1809 431.8 1810 431.8 1811 431.8 1812 431.8 1813 431.8 1814 431.8 1815 431.8 1816 431.8 1817 431.8 1818 431.8 1819 431.8 1820 431.8 1821 431.8 1822 431.8 1823 431.8 1824 431.8 1825 431.8 1826 431.8 1827 431.8 1828 431.8 1829 431.8 1830 431.8 1831 431.8 1832 431.8 1833 431.8 1834 431.8 1835 431.8 1836 431.8 1837 431.8 1838 431.8 1839 431.8 1840 431.8 1841 431.8 1842 431.8 1843 431.8 1844 431.8 1845 431.8 1846 431.8 1847 431.8 1848 431.8 1849 431.8 1850 431.8 1851 431.8 1852 431.8 1853 431.8 1854 431.8 1855 431.8 1856 431.8 1857 431.8 1858 431.8 1859 431.8 1860 431.8 1861 431.8 1862 431.8 1863 431.8 1864 431.8 1865 431.8 1866 431.8 1867 431.8 1868 431.8 1869 431.8 1870 431.8 1871 431.8 1872 431.8 1873 431.8 1874 431.8 1875 431.8 1876 431.8 1877 431.8 1878 431.8 1879 431.8 1880 431.8 1881 431.8 1882 431.8 1883 431.8 1884 431.8 1885 431.8 1886 431.8 1887 431.8 1888 431.8 1889 431.8 1890 431.8 1891 431.8 1892 431.8 1893 431.8 1894 431.8 1895 431.8 1896 431.7 1897 431.6 1898 431.4 1899 431.2 1900 430.9 1901 430.5 1902 756.3 1903 429.5 1904 429 1905 428.3 1906 427.6 1907 426.8 1908 426 1909 425.1 1910 424.1 1911 423.2 1912 422.2 1913 421.1 1914 420.1 1915 419.1 1916 418.1 1917 417.1 1918 488 1919 415.1 1920 414.1 1921 413.1 1922 412 1923 411 1924 410 1925 409 1926 408 1927 407 1928 406 1929 404.9 1930 403.9 1931 389.5 1932 374.4 1933 360.7 1934 346.4 1935 333.4 1936 320.9 1937 307.5 1938 295.5 1939 282.9 1940 269.6 1950 174.5 1951 164.2 1952 154.6 1953 145.7 1954 137.7 1955 130.5 1956 124 1957 118.1 1958 112.9 1959 108.2 1960 104.1 1961 100.7 1962 97.8 1963 95.3 1964 93.2 1965 91.2 1966 89.3 1967 87.6 1968 86 1969 84.8 1970 83.9 1971 83.3 1972 82.9 1973 82.8 1974 82.9 1975 83 1976 83.1 1977 83.1 1978 82.9 1979 82.4 1980 81.8 1981 80.8 1982 79.7 1983 78.4 1984 76.8 1985 74.8 1986 72.3 1987 69.2 1988 65.7 1989 62.1 1990 58.6 1991 55.3 1992 52.4 1993 49.9 1994 47.8 1995 46 1996 44.4 1997 43 1998 41.8 1999 40.8 2000 39.9 2001 39 2002 38.2 2003 37.4 2004 36.6 2005 35.8 2006 35 2007 34.3 2008 33.5 2009 32.8 2010 32.1 2011 31.4 2012 30.6 2013 29.9