Year Measure 1820 523.3 1821 525.7 1822 528.2 1823 530.7 1824 533.2 1825 535.7 1826 538.2 1827 540.7 1828 543.2 1829 545.8 1830 548.3 1831 550.9 1832 553.5 1833 556.1 1834 558.7 1835 561.3 1836 563.9 1837 566.6 1838 569.2 1839 571.9 1840 574.6 1841 577.3 1842 580 1843 582.7 1844 585.4 1845 588.2 1846 590.9 1847 593.7 1848 596.5 1849 599.3 1850 602.1 1851 604.9 1852 607.8 1853 610.6 1854 613.5 1855 616.4 1856 619.2 1857 622.2 1858 625.1 1859 628 1860 630.9 1861 633.9 1862 636.9 1863 639.9 1864 642.9 1865 645.9 1866 648.9 1867 651.9 1868 655 1869 658.1 1870 661.2 1871 664.3 1872 667.4 1873 670.5 1874 673.7 1875 676.8 1876 680 1877 683.2 1878 686.4 1879 689.6 1880 692.8 1881 696.1 1882 699.3 1883 702.6 1884 705.9 1885 709.2 1886 712.5 1887 715.9 1888 719.2 1889 722.6 1890 726 1891 729.4 1892 732.8 1893 736.3 1894 739.7 1895 743.2 1896 746.7 1897 750.2 1898 753.7 1899 757.2 1900 760.8 1901 764.3 1902 767.9 1903 771.5 1904 775.1 1905 778.8 1906 782.4 1907 786.1 1908 789.8 1909 793.5 1910 797.2 1911 801 1912 804.7 1913 808.5 1914 825.4 1915 842.7 1916 860.4 1917 878.5 1918 896.9 1919 915.7 1920 934.9 1921 954.5 1922 974.5 1923 995 1924 1016 1925 1037 1926 1059 1927 1081 1928 1104 1929 1127 1930 1151 1931 1175 1932 1199 1933 1224 1934 1250 1935 1276 1936 1303 1937 1330 1938 1358 1939 1387 1940 1416 1941 1446 1942 1476 1943 1507 1944 1538 1945 1571 1946 1604 1947 1637 1948 1672 1949 1707 1950 1742 1951 1774 1952 1804 1953 1833 1954 1863 1955 1893 1956 1921 1957 1950 1958 1978 1959 2004 1960 2000 1961 2041 1962 2058 1963 2086 1964 2075 1965 2091 1966 2087 1967 2005 1968 2075 1969 1885 1970 1986 1971 1924 1972 1987 1973 1820 1974 1840 1975 1932 1976 2059 1977 1942 1978 1809 1979 1876 1980 1759 1981 1692 1982 1889 1983 1877 1984 1736 1985 1747 1986 1776 1987 1793 1988 1829 1989 1744 1990 1770 1991 1712 1992 1701 1993 1619 1994 1620 1995 1658 1996 1695 1997 1732 1998 1782 1999 1824 2000 1880 2001 1918 2002 1890 2003 1965 2004 2028 2005 2084 2006 2078 2007 2124 2008 2143 2009 2132 2010 2165 2011 2163 2012 2174 2013 2198 2014 2233 2015 2273 2016 2322 2017 2371 2018 2422 2019 2474