| Year | Value | | 2021 | 51.587905813258 | | 2020 | 51.325714907204 | | 2019 | 51.114408458473 | | 2018 | 51.101590236399 | | 2017 | 50.945829416654 | | 2016 | 50.748894913885 | | 2015 | 50.989333685511 | | 2014 | 50.88057301337 | | 2013 | 50.837845606457 | | 2012 | 51.0475983313 | | 2011 | 50.989333685511 | | 2010 | 50.899994561966 | | 2009 | 50.767928031509 | | 2008 | 50.884457323089 | | 2007 | 50.884457323089 | | 2006 | 50.107595379225 | | 2005 | 50.107595379225 | | 2004 | 49.719164407293 | | 2003 | 49.719164407293 | | 2002 | 49.719164407293 | | 2001 | 49.719164407293 | | 2000 | 49.719164407293 |
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