Year | Value | 2021 | 13,969 | 2020 | 8,743.635 | 2019 | 26,305 | 2018 | 27,601 | 2017 | 27,995 | 2016 | 28,670 | 2015 | 28,671 | 2014 | 31,662 | 2013 | 29,114 | 2012 | 26,622 | 2011 | 24,699 | 2010 | 20,961.277087462 | 2009 | 19,339 | 2008 | 21,056 | 2007 | 22,465 | 2006 | 24,879 | 2005 | 23,964 | 2004 | 23,660 | 2003 | 22,063 | 2002 | 19,407 | 2001 | 26,059 | 2000 | 37,098 | 1999 | 32,000 | 1998 | 19,400 | 1997 | 19,100 | 1996 | 20,900 | 1995 | 20,000 | 1994 | 18,800 | 1993 | 15,500 | 1992 | 14,600 | 1991 | 12,400 | 1990 | 10,700 | 1989 | 9,600 | 1988 | 9,400 | 1987 | 9,500 | 1986 | 9,700 | 1985 | 9,400 | 1984 | 9,200 | 1983 | 8,300 | 1982 | 9,000 | 1981 | 8,100 | 1980 | 8,100 | 1979 | 8,700 | 1978 | 11,900 | 1977 | 12,000 | 1976 | 9,500 | 1975 | 9,200 | 1974 | 9,000 | 1973 | 8,800 | 1972 | 8,700 | 1971 | 9,400 | 1970 | 8,800 |
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