Year | Value | 2022 | 14.619007721275 | 2021 | 14.609223699637 | 2020 | 14.6960943129 | 2019 | 16.955144696696 | 2018 | 18.964030448683 | 2017 | 18.962137072775 | 2016 | 18.974146542803 | 2015 | 17.743341838534 | 2014 | 16.911929931755 | 2013 | 16.09649206305 | 2012 | 15.477600588714 | 2011 | 14.683335407549 | 2010 | 13.946848039196 | 2009 | 13.152580737102 | 2008 | 12.357370164746 | 2007 | 11.656485641155 | 2006 | 10.979221901218 | 2005 | 10.652476827489 | 2004 | 10.246504654797 | 2003 | 9.9863612171156 | 2002 | 9.6917762720872 | 2001 | 9.4613138835582 | 2000 | 9.1285884642089 | 1999 | 9.0643245836842 | 1998 | 8.8779731061124 | 1997 | 8.7178876665881 | 1996 | 8.6178572130137 | 1995 | 8.5415788431722 | 1994 | 8.4983588690735 | 1993 | 8.4908570397222 | 1992 | 8.4450579204744 | 1991 | 8.4244460712862 |
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