Year | Value | 2021 | 27,092.684 | 2020 | 31,284.792 | 2019 | 47,733 | 2018 | 54,000 | 2017 | 48,017 | 2016 | 49,095 | 2015 | 48,535 | 2014 | 53,366 | 2013 | 34,188 | 2012 | 30,640 | 2011 | 28,393 | 2010 | 26,395 | 2009 | 30,267 | 2008 | 33,433 | 2007 | 34,402 | 2006 | 33,723 | 2005 | 33,211 | 2004 | 29,817 | 2003 | 24,455 | 2002 | 26,493 | 2001 | 29,395 | 2000 | 31,416 | 1999 | 31,100 | 1998 | 9,300 | 1997 | 9,100 | 1996 | 20,100 | 1995 | 19,300 | 1994 | 17,700 | 1993 | 17,700 | 1992 | 16,700 | 1991 | 18,900 | 1990 | 18,900 | 1989 | 20,200 | 1988 | 19,500 | 1987 | 18,300 | 1986 | 18,000 | 1985 | 18,100 | 1984 | 8,400 | 1983 | 9,100 | 1982 | 9,200 | 1981 | 8,200 | 1980 | 32,000 | 1979 | 29,900 | 1978 | 17,200 | 1977 | 16,500 | 1976 | 16,000 | 1975 | 15,900 |
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