| Year | Value | | 2021 | 6.6944589195764 | | 2020 | 3.3816593723788 | | 2019 | 4.4703666076019 | | 2018 | 2.8782972364787 | | 2017 | 3.6833294441225 | | 2016 | 7.0424476295477 | | 2015 | 15.53440505284 | | 2014 | 7.8234118386553 | | 2013 | 6.753710262209 | | 2012 | 5.0747430079914 | | 2011 | 8.4404648593256 | | 2010 | 6.8493923025507 | | 2009 | 11.647329576412 | | 2008 | 14.110767784044 | | 2007 | 9.0072986886107 | | 2006 | 9.6686545478926 | | 2005 | 12.685303950735 | | 2004 | 10.888615732622 | | 2003 | 13.663293022866 | | 2002 | 15.788730791446 | | 2001 | 21.477007211716 | | 2000 | 20.798760655871 | | 1999 | 85.746494096064 | | 1998 | 27.685679807674 | | 1997 | 14.761329268806 | | 1996 | 47.752012200994 | | 1995 | 197.41426808425 | | 1994 | 307.72263555319 | | 1993 | 874.24572038019 |
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