| Year | Value | | 2022 | 59.85053209242 | | 2021 | 59.593843581297 | | 2020 | 59.36357880084 | | 2019 | 60.467217519166 | | 2018 | 62.889917626344 | | 2017 | 64.129844593267 | | 2016 | 64.824658680174 | | 2015 | 65.080931230198 | | 2014 | 64.96760210977 | | 2013 | 64.876093863737 | | 2012 | 64.775916365179 | | 2011 | 63.487984697375 | | 2010 | 63.294025495602 | | 2009 | 64.747635617728 | | 2008 | 65.371126400873 | | 2007 | 65.958600738022 | | 2006 | 64.574535500746 | | 2005 | 63.45376752462 | | 2004 | 62.112936410383 | | 2003 | 59.588682637306 | | 2002 | 60.08049953823 | | 2001 | 59.04391788366 | | 2000 | 58.030556915737 | | 1999 | 59.231061270599 | | 1998 | 60.381826250877 | | 1997 | 63.87238075226 | | 1996 | 61.273979924228 | | 1995 | 62.100544629301 | | 1994 | 61.711771933747 | | 1993 | 61.893728995722 | | 1992 | 61.596878501911 | | 1991 | 61.329806608132 |
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