| Year | Value | | 2021 | 24.266059678534 | | 2020 | 24.133216286134 | | 2019 | 24.066794589933 | | 2018 | 24.127001390583 | | 2017 | 24.097480636716 | | 2016 | 24.028339923712 | | 2015 | 24.393465037328 | | 2014 | 24.319663152661 | | 2013 | 24.257514197152 | | 2012 | 24.300241604064 | | 2011 | 24.129331976414 | | 2010 | 24.063298711186 | | 2009 | 23.993381136238 | | 2008 | 24.082720259783 | | 2007 | 23.694289287851 | | 2006 | 23.305858315919 | | 2005 | 23.305858315919 | | 2004 | 24.082720259783 | | 2003 | 24.082720259783 | | 2002 | 24.082720259783 | | 2001 | 24.082720259783 | | 2000 | 24.082720259783 |
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