| Year | Value | | 2023 | 47.899710103475 | | 2022 | 47.963069253114 | | 2021 | 47.30266889688 | | 2020 | 49.476877496001 | | 2019 | 49.71691360654 | | 2018 | 48.534245588624 | | 2017 | 49.403156293886 | | 2016 | 49.061656897316 | | 2015 | 48.42280583104 | | 2014 | 47.357815732999 | | 2013 | 41.879809551039 | | 2012 | 41.670350080028 | | 2011 | 42.326836475353 | | 2010 | 44.544999093723 | | 2009 | 44.716454874972 | | 2008 | 43.309123536464 | | 2007 | 40.904776843633 | | 2006 | 43.759302983807 | | 2005 | 43.794073330636 | | 2004 | 43.943985662785 | | 2003 | 40.635245231235 | | 2002 | 40.067886967764 | | 2001 | 40.49182060283 | | 2000 | 38.182276686379 | | 1999 | 38.259657053028 | | 1998 | 36.495735691672 | | 1997 | 37.661366859744 | | 1996 | 37.698442558424 | | 1995 | 35.652575440982 | | 1994 | 34.763709438282 | | 1993 | 34.332037622395 | | 1992 | 31.230836113413 | | 1991 | 30.707890925265 |
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