| Year | Value | | 2021 | 64.313524590164 | | 2020 | 64.415983606557 | | 2019 | 64.518442622951 | | 2018 | 64.673913043478 | | 2017 | 64.783099169316 | | 2016 | 64.879114566772 | | 2015 | 65.031556262507 | | 2014 | 65.144206096685 | | 2013 | 65.249522714676 | | 2012 | 65.430068852122 | | 2011 | 65.613746270192 | | 2010 | 65.70987654321 | | 2009 | 65.896352771482 | | 2008 | 66.035673780802 | | 2007 | 66.175196037969 | | 2006 | 66.294384805945 | | 2005 | 66.406814661848 | | 2004 | 66.519314191283 | | 2003 | 66.625 | | 2002 | 66.723835106932 | | 2001 | 66.850320446558 | | 2000 | 67.136636947958 | | 1999 | 67.214389384201 | | 1998 | 67.292141820444 | | 1997 | 67.369894256687 | | 1996 | 67.44764669293 | | 1995 | 67.525399129173 | | 1994 | 67.603151565416 | | 1993 | 67.680904001659 | | 1992 | 67.758656437902 | | 1991 | 67.836408874145 | | 1990 | 67.914161310388 |
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