| Year | Value | | 2023 | 58.679461035913 | | 2022 | 57.791335069246 | | 2021 | 55.760513501549 | | 2020 | 54.478793216888 | | 2019 | 57.074566965791 | | 2018 | 56.988246090785 | | 2017 | 57.64096689536 | | 2016 | 55.765863888187 | | 2015 | 56.231474167725 | | 2014 | 56.298158395408 | | 2013 | 55.42198532225 | | 2012 | 52.209053536645 | | 2011 | 53.394421626349 | | 2010 | 52.662619961286 | | 2009 | 49.290730686057 | | 2008 | 51.925727676269 | | 2007 | 49.005162816838 | | 2006 | 47.367785053163 | | 2005 | 47.071205682253 | | 2004 | 43.883680974925 | | 2003 | 45.179501311338 | | 2002 | 43.387211293489 | | 2001 | 44.913617780302 | | 2000 | 46.251532280204 | | 1999 | 47.493369957143 | | 1998 | 46.445573535939 | | 1997 | 46.530642787395 | | 1996 | 46.45624590547 | | 1995 | 46.407039234314 | | 1994 | 46.178889522947 | | 1993 | 46.209456029238 | | 1992 | 46.254980811253 | | 1991 | 46.348551837506 |
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