| Year | Value | | 2022 | 86.515098820985 | | 2021 | 86.890421226203 | | 2020 | 87.583353825235 | | 2019 | 87.65149690749 | | 2018 | 87.925252445519 | | 2017 | 87.012306457323 | | 2016 | 86.091979381111 | | 2015 | 84.329970711445 | | 2014 | 84.384274120283 | | 2013 | 81.92215356967 | | 2012 | 80.252225174392 | | 2011 | 78.217214986778 | | 2010 | 78.162645609795 | | 2009 | 79.14353150736 | | 2008 | 79.124938725082 | | 2007 | 79.218668618368 | | 2006 | 77.024185100689 | | 2005 | 75.105697042714 | | 2004 | 75.880386305014 | | 2003 | 75.563805852201 | | 2002 | 75.892140243072 | | 2001 | 75.74684812865 | | 2000 | 76.136495742228 | | 1999 | 75.158913134399 | | 1998 | 75.342521609236 | | 1997 | 74.076709218052 | | 1996 | 71.440305811258 | | 1995 | 71.19827536182 | | 1994 | 71.36038588766 | | 1993 | 72.031045431624 | | 1992 | 72.702402658247 | | 1991 | 72.940411672496 |
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