Year Years
1800 420
1801 420
1802 420
1803 420
1804 420
1805 420
1806 420
1807 420
1808 420
1809 420
1810 420
1811 420
1812 420
1813 420
1814 420
1815 420
1816 420
1817 420
1818 420
1819 420
1820 420
1821 420
1822 420
1823 420
1824 420
1825 420
1826 420
1827 420
1828 420
1829 420
1830 420
1831 420
1832 420
1833 420
1834 420
1835 420
1836 420
1837 420
1838 420
1839 420
1840 420
1841 420
1842 420
1843 420
1844 420
1845 420
1846 420
1847 420
1848 420
1849 420
1850 420
1851 420
1852 420
1853 420
1854 420
1855 420
1856 420
1857 420
1858 420
1859 420
1860 420
1861 420
1862 420
1863 420
1864 420
1865 420
1866 420
1867 420
1868 420
1869 420
1870 420
1871 420
1872 420
1873 420
1874 420
1875 420
1876 420
1877 420
1878 420
1879 420
1880 420
1881 420
1882 420
1883 420
1884 420
1885 420
1886 420
1887 420
1888 420
1889 420
1890 420
1891 420
1892 420
1893 420
1894 420
1895 420
1896 419.9
1897 419.8
1898 419.7
1899 419.4
1900 419.1
1901 418.8
1902 418.3
1903 417.9
1904 417.3
1905 416.7
1906 416
1907 415.2
1908 414.4
1909 413.5
1910 412.6
1911 411.6
1912 410.7
1913 409.7
1914 408.7
1915 407.7
1916 406.7
1917 405.8
1918 404.8
1919 403.8
1920 402.8
1921 401.8
1922 400.8
1923 399.8
1924 398.9
1925 397.9
1926 396.9
1927 395.9
1928 394.9
1929 393.9
1930 392.9
1931 391.9
1932 391
1933 390
1934 389
1935 388
1936 387
1937 386
1938 385.1
1939 384.1
1940 383.1
1941 382.1
1942 381.1
1943 380.1
1944 379.1
1945 378.1
1946 353.3
1947 328.5
1948 305.9
1949 283.3
1950 262.6
1978 177.8
1979 171.1
1980 164.6
1981 158.4
1982 152.5
1983 146.6
1984 140.9
1985 135.2
1986 129.6
1987 123.9
1988 118.4
1989 113
1990 107.9
1991 103
1992 98.4
1993 93.9
1994 89.6
1995 85.4
1996 81.2
1997 77
1998 72.8
1999 68.7
2000 64.6
2001 60.5
2002 56.7
2003 53
2004 49.6
2005 46.4
2006 43.6
2007 41.1
2008 39
2009 37.2
2010 35.7
2011 34.2
2012 32.9
2013 31.8