Year | Value | 2014 | 22.267234318456 | 2013 | 22.355470855954 | 2012 | 22.536109619858 | 2011 | 21.883536531583 | 2010 | 21.577396419831 | 2009 | 22.206058993936 | 2008 | 19.105789902884 | 2007 | 26.084767158829 | 2006 | 25.860613464409 | 2005 | 34.40911441313 | 2004 | 35.218204069556 | 2003 | 29.670710831408 | 2002 | 26.85122337071 | 2001 | 28.373512087331 | 2000 | 28.265933597122 | 1999 | 29.278222949576 | 1998 | 28.803322789488 | 1997 | 25.121243656749 | 1996 | 27.866228962209 | 1995 | 26.792515615854 | 1994 | 25.531267695766 | 1993 | 23.184900088485 | 1992 | 19.355382884603 |
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