Year Years 1800 461.6 1801 461.6 1802 461.6 1803 461.6 1804 461.6 1805 461.6 1806 461.6 1807 461.6 1808 461.6 1809 461.6 1810 461.6 1811 461.6 1812 461.6 1813 461.6 1814 461.6 1815 461.6 1816 461.6 1817 461.6 1818 461.6 1819 461.6 1820 461.6 1821 461.6 1822 461.6 1823 461.6 1824 461.6 1825 461.6 1826 461.6 1827 461.6 1828 461.6 1829 461.6 1830 461.6 1831 461.6 1832 461.6 1833 461.6 1834 461.6 1835 461.6 1836 461.6 1837 461.6 1838 461.6 1839 461.6 1840 461.6 1841 461.6 1842 461.6 1843 461.6 1844 461.6 1845 461.6 1846 461.6 1847 461.6 1848 461.6 1849 461.6 1850 461.6 1851 461.6 1852 461.6 1853 461.6 1854 461.6 1855 461.6 1856 461.6 1857 461.6 1858 461.6 1859 461.6 1860 461.6 1861 461.6 1862 461.6 1863 461.6 1864 461.6 1865 461.6 1866 461.6 1867 461.6 1868 461.6 1869 461.6 1870 461.6 1871 461.6 1872 461.6 1873 461.6 1874 461.6 1875 461.6 1876 461.6 1877 461.6 1878 461.6 1879 461.6 1880 461.6 1881 461.6 1882 461.6 1883 461.6 1884 461.6 1885 461.6 1886 461.6 1887 461.6 1888 461.6 1889 461.6 1890 461.6 1891 461.6 1892 461.6 1893 461.6 1894 461.6 1895 461.6 1896 461.5 1897 461.4 1898 461.2 1899 460.9 1900 460.6 1901 460.2 1902 459.7 1903 459.2 1904 458.6 1905 457.9 1906 457.1 1907 456.3 1908 455.4 1909 454.4 1910 453.4 1911 452.4 1912 451.3 1913 450.2 1914 449.1 1915 448.1 1916 447 1917 445.9 1918 444.8 1919 443.7 1920 442.6 1921 441.6 1922 440.5 1923 439.4 1924 438.3 1925 437.2 1926 436.1 1927 435.1 1928 434 1929 432.9 1930 431.8 1931 421.7 1932 410.6 1933 400.9 1934 391.4 1935 382.1 1936 371.7 1937 362.8 1938 353.9 1939 344.2 1940 335.6 1941 327.3 1942 319.1 1943 310 1944 302 1945 294.2 1955 208.8 1956 204 1957 199.5 1958 195.3 1959 191.1 1960 187.1 1961 183.3 1962 179.6 1963 176 1964 172.7 1965 169.5 1966 166.5 1967 163.4 1968 160.5 1969 157.5 1970 154.6 1971 151.6 1972 148.4 1973 144.8 1974 141 1975 136.7 1976 132 1977 127.1 1978 121.8 1979 116.2 1980 110.3 1981 104.1 1982 97.9 1983 91.7 1984 85.8 1985 80.2 1986 75.1 1987 70.6 1988 66.5 1989 62.8 1990 59.5 1991 56.4 1992 53.4 1993 50.5 1994 47.6 1995 44.7 1996 41.9 1997 39.2 1998 36.7 1999 34.5 2000 32.4 2001 30.4 2002 28.6 2003 26.9 2004 25.2 2005 23.6 2006 22.1 2007 20.7 2008 19.5 2009 18.5 2010 17.7 2011 17 2012 16.3 2013 15.7