| Year | Value | | 2021 | 1,732.788 | | 2020 | 3,450 | | 2018 | 3,444 | | 2017 | 3,444 | | 2016 | 4,231 | | 2015 | 4,145 | | 2014 | 3,730 | | 2013 | 27,684 | | 2012 | 11,560.367853924 | | 2011 | 10,020.705611279 | | 2010 | 7,077 | | 2009 | 5,937 | | 2008 | 5,917 | | 2007 | 7,272 | | 2006 | 6,819 | | 2005 | 4,410 | | 2004 | 4,269 | | 2003 | 3,950 | | 2002 | 5,050 | | 2001 | 8,848 | | 2000 | 13,603 | | 1999 | 15,300 | | 1998 | 17,800 | | 1997 | 17,700 | | 1996 | 10,000 | | 1995 | 9,900 | | 1994 | 9,800 | | 1993 | 11,000 | | 1992 | 13,500 | | 1991 | 13,300 | | 1990 | 10,300 | | 1989 | 10,000 | | 1988 | 9,700 | | 1987 | 8,800 | | 1986 | 8,900 | | 1985 | 9,400 | | 1984 | 10,600 | | 1983 | 10,800 | | 1982 | 11,100 | | 1981 | 11,100 | | 1980 | 10,900 |
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