| Year | Value | | 2022 | 36.765965076734 | | 2021 | 33.710288869921 | | 2020 | 32.770890124092 | | 2019 | 31.592837953716 | | 2018 | 26.652536283071 | | 2017 | 24.226588556142 | | 2016 | 21.227726297582 | | 2015 | 21.342028679297 | | 2014 | 21.04028629425 | | 2013 | 19.932416979044 | | 2012 | 19.219955424982 | | 2011 | 16.879902706404 | | 2010 | 18.529134155295 | | 2009 | 18.80388627859 | | 2008 | 16.713659273165 | | 2007 | 19.215014956022 | | 2006 | 19.863308963025 | | 2005 | 15.339384376898 | | 2004 | 14.396256373636 | | 2003 | 16.238778053273 | | 2002 | 16.519758524162 | | 2001 | 16.324305244141 | | 2000 | 14.295618983659 | | 1999 | 13.020769071799 | | 1998 | 7.2339920896352 | | 1997 | 8.5399863263003 | | 1996 | 4.6745981957533 | | 1995 | 5.616724784623 |
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