| Year | Value | | 2025 | 71.451171199027 | | 2024 | 71.159020967611 | | 2023 | 71.401494712751 | | 2022 | 70.698363395988 | | 2021 | 69.909653525329 | | 2020 | 69.597381987792 | | 2019 | 68.224144965616 | | 2018 | 67.751251011954 | | 2017 | 67.024322881695 | | 2016 | 67.313529426369 | | 2015 | 66.584184906023 | | 2014 | 65.819658303003 | | 2013 | 65.484406157489 | | 2012 | 64.338911913411 | | 2011 | 63.114853454823 | | 2010 | 62.301413008366 | | 2009 | 61.42819787709 | | 2008 | 62.394721238229 | | 2007 | 61.86330161371 | | 2006 | 60.303322111735 | | 2005 | 58.071489402237 | | 2004 | 55.860258105328 | | 2003 | 52.015022740881 | | 2002 | 51.136529569238 | | 2001 | 48.55593756026 | | 2000 | 49.961946152857 | | 1999 | 49.485915782391 | | 1998 | 49.157384426913 | | 1997 | 48.792229955701 | | 1996 | 48.622403907366 | | 1995 | 48.367864440804 | | 1994 | 48.17891479347 | | 1993 | 48.074685372485 | | 1992 | 47.838781987412 | | 1991 | 47.64969668606 |
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