| Year | Value | | 2025 | 69.154763457832 | | 2024 | 69.165405938964 | | 2023 | 68.646087417107 | | 2022 | 68.150817895877 | | 2021 | 68.090377748096 | | 2020 | 69.640197879853 | | 2019 | 69.737793393071 | | 2018 | 70.065224003879 | | 2017 | 70.252036847171 | | 2016 | 70.033348494244 | | 2015 | 69.599092030049 | | 2014 | 69.486532972145 | | 2013 | 68.73038489084 | | 2012 | 68.662048837427 | | 2011 | 67.966651353345 | | 2010 | 68.174232633402 | | 2009 | 67.263764062248 | | 2008 | 67.968338976218 | | 2007 | 67.142587329813 | | 2006 | 67.132560405502 | | 2005 | 66.279259046755 | | 2004 | 66.259438683681 | | 2003 | 65.832642696396 | | 2002 | 65.86568397599 | | 2001 | 65.888594206357 | | 2000 | 66.320097691798 | | 1999 | 64.176696367606 | | 1998 | 63.603881395842 | | 1997 | 61.239693010626 | | 1996 | 62.1175843103 | | 1995 | 60.935388834467 | | 1994 | 59.071542015876 | | 1993 | 57.779688176714 | | 1992 | 58.807599454045 | | 1991 | 58.670158758139 |
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