| Year | Value | | 2022 | 63.299557647904 | | 2021 | 63.092528996278 | | 2020 | 62.929889145361 | | 2019 | 62.542614420704 | | 2018 | 62.180449681911 | | 2017 | 61.870262898849 | | 2016 | 61.70517024915 | | 2015 | 61.677529243089 | | 2014 | 61.761610253402 | | 2013 | 62.145335770887 | | 2012 | 62.945560434872 | | 2011 | 62.601833966645 | | 2010 | 63.186976520881 | | 2009 | 61.81989153214 | | 2008 | 61.770369728328 | | 2007 | 53.74040465861 | | 2006 | 55.501695928984 | | 2005 | 54.269241799306 | | 2004 | 52.860688274343 | | 2003 | 51.66506919133 | | 2002 | 50.428144230005 | | 2001 | 49.238902076342 | | 2000 | 48.912721850053 | | 1999 | 48.588075881386 | | 1998 | 48.196531156679 | | 1997 | 47.579618859637 | | 1996 | 47.169805895415 | | 1995 | 46.793958144559 | | 1994 | 46.555783116237 | | 1993 | 46.378463924163 | | 1992 | 46.250039780342 | | 1991 | 46.096194216732 |
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