Year | Value | 2021 | 18,619.4 | 2020 | 18,609.4 | 2019 | 18,589.4 | 2018 | 18,569.4 | 2017 | 18,569.4 | 2016 | 18,579.4 | 2015 | 18,589.4 | 2014 | 18,520.4 | 2013 | 18,484.4 | 2012 | 18,399.4 | 2011 | 18,474.4 | 2010 | 18,462.4 | 2009 | 18,688.4 | 2008 | 18,568.4 | 2007 | 18,710.2 | 2006 | 18,769.1 | 2005 | 18,777 | 2004 | 18,927.633 | 2003 | 19,032.667 | 2002 | 18,966 | 2001 | 19,117.333 | 2000 | 19,153.667 | 1999 | 19,155.4 | 1998 | 19,101.333 | 1997 | 19,201.267 | 1996 | 19,290.2 | 1995 | 19,301.133 | 1994 | 19,351.067 | 1993 | 19,398 | 1992 | 19,042.933 | 1991 | 18,968.867 | 1990 | 18,884.8 | 1989 | 18,770.733 | 1988 | 18,685.667 | 1987 | 18,640.6 | 1986 | 18,517.333 | 1985 | 18,434.667 | 1984 | 18,383 | 1983 | 18,321.333 | 1982 | 19,036.917 | 1981 | 19,692.5 | 1980 | 20,187.083 | 1979 | 20,681.667 | 1978 | 21,227.25 | 1977 | 21,644.833 | 1976 | 22,092.417 | 1975 | 22,560 | 1974 | 22,569 | 1973 | 22,550 | 1972 | 22,410 | 1971 | 22,400 | 1970 | 22,300 | 1969 | 22,370 | 1968 | 22,340 | 1967 | 22,320 | 1966 | 22,320 | 1965 | 22,180 | 1964 | 22,430 | 1963 | 22,400 | 1962 | 22,370 | 1961 | 22,340 |
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