Year | Value | 2018 | 55.5 | 2017 | 55.9 | 2016 | 56.5 | 2015 | 56.6 | 2014 | 54.6 | 2013 | 55.2 | 2012 | 55.7 | 2011 | 56 | 2010 | 56.3 | 2009 | 57.5 | 2008 | 58 | 2007 | 58.8 | 2006 | 59.8 | 2005 | 60.9 | 2004 | 62.6 | 2003 | 65.1 | 2002 | 65.5 | 2001 | 65.7 | 1999 | 69.1 | 1998 | 67.3 | 1997 | 67.7 | 1996 | 68.1 | 1995 | 68.2 | 1994 | 67.5 | 1993 | 66 |
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