| Year | Value | | 2022 | 83.458854981742 | | 2021 | 82.99744119661 | | 2020 | 82.314507900169 | | 2019 | 79.311798603667 | | 2018 | 77.358141851595 | | 2017 | 76.746552505935 | | 2016 | 76.0931438792 | | 2015 | 74.037183475385 | | 2014 | 73.932368595615 | | 2013 | 72.306677219681 | | 2012 | 73.553770881301 | | 2011 | 72.400591503826 | | 2010 | 72.299801348227 | | 2009 | 72.401257583418 | | 2008 | 72.145493141737 | | 2007 | 72.638154163881 | | 2006 | 71.932178991017 | | 2005 | 71.82908740513 | | 2004 | 75.401322426403 | | 2003 | 72.737896643086 | | 2002 | 70.666601964295 | | 2001 | 70.054671331133 | | 2000 | 74.329551952223 | | 1999 | 74.98801365285 | | 1998 | 77.435175581568 | | 1997 | 78.158110765354 | | 1996 | 78.89326735998 | | 1995 | 78.984042372977 | | 1994 | 78.116896104613 | | 1993 | 78.457320843584 | | 1992 | 79.265307414176 | | 1991 | 78.838736801058 |
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