Year | Value | 2021 | 8.11 | 2020 | 7.46 | 2019 | 8.14 | 2018 | 8.14 | 2017 | 8.11 | 2016 | 8.28 | 2015 | 8.1 | 2014 | 8.14 | 2013 | 8.24 | 2012 | 8.34 | 2011 | 8.4 | 2010 | 8.33 | 2009 | 7.95 | 2008 | 8.46 | 2007 | 8 | 2006 | 7.17 | 2005 | 8.41 | 2004 | 9.7 | 2003 | 13.44 | 2002 | 13.39 | 2001 | 13.59 | 2000 | 13.6 | 1999 | 10.78 | 1998 | 12.04 | 1997 | 11.8 | 1996 | 11.67 | 1995 | 9.72 | 1994 | 8.75 | 1991 | 15.35 |
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