| Year | Value | | 2021 | 84.40243902439 | | 2020 | 81.658536585366 | | 2019 | 84.160975609756 | | 2018 | 83.041463414634 | | 2017 | 83.746341463415 | | 2016 | 82.258536585366 | | 2015 | 82.656097560976 | | 2014 | 82.073170731707 | | 2013 | 82.260975609756 | | 2012 | 82.382926829268 | | 2011 | 81.792682926829 | | 2010 | 81.841463414634 | | 2009 | 81.5 | | 2008 | 82.682926829268 | | 2007 | 81.295121951219 | | 2006 | 80.948780487805 | | 2005 | 80.668292682927 | | 2004 | 81.770731707317 | | 2003 | 79.960975609756 | | 2002 | 79.636585365854 | | 2001 | 79.275609756098 | | 2000 | 76.826829268293 | | 1999 | 79.109756097561 | | 1998 | 77.746341463415 | | 1997 | 76.046341463415 | | 1996 | 76.836585365854 | | 1995 | 77.390243902439 | | 1994 | 78.421951219512 |
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