Year | Value | 2021 | 39,490 | 2020 | 39,490 | 2019 | 39,490 | 2018 | 39,490 | 2017 | 39,490 | 2016 | 39,490 | 2015 | 39,490 | 2014 | 39,490 | 2013 | 39,486.5 | 2012 | 38,366.5 | 2011 | 40,176.3 | 2010 | 39,303.8 | 2009 | 38,009.7 | 2008 | 37,122.3 | 2007 | 36,237.2 | 2006 | 40,298.8 | 2005 | 38,120.2 | 2004 | 37,727.3 | 2003 | 35,666.7 | 2002 | 32,300.8 | 2001 | 30,015.2 | 2000 | 28,100 | 1999 | 28,040 | 1998 | 28,090 | 1997 | 28,090 | 1996 | 28,100 | 1995 | 28,100 | 1994 | 28,100 | 1993 | 28,110 | 1992 | 28,150 | 1991 | 28,250 | 1990 | 28,250 | 1989 | 28,250 | 1988 | 28,250 | 1987 | 28,240 | 1986 | 28,190 | 1985 | 28,140 | 1984 | 27,640 | 1983 | 27,490 | 1982 | 27,440 | 1981 | 27,290 | 1980 | 27,240 | 1979 | 27,190 | 1978 | 27,090 | 1977 | 26,990 | 1976 | 26,940 | 1975 | 26,890 | 1974 | 26,840 | 1973 | 26,790 | 1972 | 26,740 | 1971 | 26,690 | 1970 | 26,640 | 1969 | 26,590 | 1968 | 26,540 | 1967 | 26,440 | 1966 | 26,390 | 1965 | 26,340 | 1964 | 26,290 | 1963 | 26,240 | 1962 | 26,170 | 1961 | 26,120 |
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