| Year | Value | | 2022 | 45.522387108092 | | 2021 | 45.130079352528 | | 2020 | 44.825751707225 | | 2019 | 44.742152959658 | | 2018 | 45.241853194855 | | 2017 | 46.171131750436 | | 2016 | 47.497438320932 | | 2015 | 48.721843547692 | | 2014 | 50.491600844866 | | 2013 | 50.558656195511 | | 2012 | 50.758472848552 | | 2011 | 51.292502395665 | | 2010 | 51.928155251412 | | 2009 | 51.62309285729 | | 2008 | 51.669428718044 | | 2007 | 51.589185584241 | | 2006 | 51.641018513592 | | 2005 | 51.584110344402 | | 2004 | 51.352361101795 | | 2003 | 51.133401204832 | | 2002 | 50.90121524949 | | 2001 | 50.670506829497 | | 2000 | 50.426573732716 | | 1999 | 49.813001717108 | | 1998 | 49.43982704296 | | 1997 | 49.34812630403 | | 1996 | 49.05269882557 | | 1995 | 48.67666386183 | | 1994 | 48.331620013819 | | 1993 | 48.073607631408 | | 1992 | 47.865363932228 | | 1991 | 47.581307040972 |
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