Year | Value | 2022 | 10.847821431886 | 2021 | 10.670738228374 | 2020 | 10.559112741739 | 2019 | 10.598333959514 | 2018 | 10.603528890639 | 2017 | 10.676110807516 | 2016 | 10.708426419078 | 2015 | 10.743554258089 | 2014 | 10.932402138915 | 2013 | 10.622490513253 | 2012 | 10.153380790428 | 2011 | 9.9306250544284 | 2010 | 9.8275683774466 | 2009 | 9.7573801268175 | 2008 | 9.626496014109 | 2007 | 9.4596951753707 | 2006 | 9.2537962824851 | 2005 | 9.0975455696171 | 2004 | 8.9347075569345 | 2003 | 8.6602601249115 | 2002 | 8.4268298063535 | 2001 | 8.2852626998365 | 2000 | 8.4254762021211 | 1999 | 8.3823163770301 | 1998 | 8.4231378763867 | 1997 | 8.469653027868 | 1996 | 8.5489290904667 | 1995 | 8.5987500941194 | 1994 | 8.6888201684944 | 1993 | 8.7453687484739 | 1992 | 8.8120579578181 | 1991 | 8.9065827178222 |
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