| Year | Value | | 2021 | 405.023 | | 2020 | 367.394 | | 2019 | 1,354 | | 2018 | 2,327 | | 2017 | 2,327 | | 2016 | 1,818 | | 2015 | 1,687 | | 2014 | 1,644 | | 2013 | 1,644 | | 2012 | 3,201.1669216461 | | 2011 | 3,172 | | 2010 | 3,340.3901234568 | | 2009 | 4,376 | | 2008 | 4,416 | | 2007 | 5,888 | | 2006 | 5,528 | | 2005 | 5,446 | | 2004 | 5,290 | | 2003 | 4,940 | | 2002 | 4,620 | | 2001 | 4,708 | | 2000 | 4,806 | | 1999 | 4,400 | | 1998 | 3,600 | | 1997 | 3,600 | | 1996 | 3,500 | | 1995 | 3,500 | | 1994 | 3,400 | | 1993 | 3,300 | | 1992 | 3,800 | | 1991 | 4,000 | | 1990 | 3,600 | | 1989 | 3,500 | | 1988 | 1,600 | | 1987 | 3,000 | | 1986 | 4,400 | | 1985 | 5,700 | | 1984 | 6,000 | | 1983 | 3,700 | | 1982 | 4,500 | | 1981 | 3,500 | | 1980 | 3,300 | | 1979 | 4,200 | | 1978 | 4,700 | | 1977 | 4,900 | | 1976 | 3,900 | | 1975 | 5,000 | | 1974 | 4,300 | | 1973 | 4,300 | | 1972 | 4,400 | | 1971 | 4,400 | | 1970 | 3,800 |
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