| Year | Value | | 2022 | 66.653601622301 | | 2021 | 66.579785373361 | | 2020 | 66.731293072269 | | 2019 | 67.295548915912 | | 2018 | 67.306337950697 | | 2017 | 67.415864525633 | | 2016 | 67.425438649752 | | 2015 | 67.123213208934 | | 2014 | 66.724128188031 | | 2013 | 66.319417943645 | | 2012 | 66.281691876113 | | 2011 | 66.236273105827 | | 2010 | 66.085212640777 | | 2009 | 66.03435614201 | | 2008 | 66.320674289025 | | 2007 | 65.982158973045 | | 2006 | 65.195658345731 | | 2005 | 64.623409117217 | | 2004 | 64.190889809605 | | 2003 | 63.926154409089 | | 2002 | 63.969175452429 | | 2001 | 63.72850768225 | | 2000 | 63.645974565785 | | 1999 | 63.482178996532 | | 1998 | 63.559492149775 | | 1997 | 63.478816177335 | | 1996 | 63.394214221243 | | 1995 | 63.161063733137 | | 1994 | 62.656173079805 | | 1993 | 62.56749939795 | | 1992 | 62.674658147749 | | 1991 | 62.986311930801 |
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