| Year | Value | | 2022 | 86.379576618491 | | 2021 | 86.359156123467 | | 2020 | 86.322051953595 | | 2019 | 86.392093259804 | | 2018 | 86.378396612538 | | 2017 | 86.218924261008 | | 2016 | 86.095386871197 | | 2015 | 86.0096078939 | | 2014 | 85.380829226061 | | 2013 | 85.084148518984 | | 2012 | 84.676045908923 | | 2011 | 85.002488515947 | | 2010 | 85.501791567854 | | 2009 | 85.246592716955 | | 2008 | 84.919809533994 | | 2007 | 84.621767102432 | | 2006 | 84.900929926045 | | 2005 | 84.657189646484 | | 2004 | 84.438154994348 | | 2003 | 85.062006631458 | | 2002 | 84.85195788387 | | 2001 | 84.631939634472 | | 2000 | 84.601779063966 | | 1999 | 84.39803752923 | | 1998 | 85.49435369792 | | 1997 | 86.051486824325 | | 1996 | 85.322481909848 | | 1995 | 88.453643203416 | | 1994 | 86.341195994838 | | 1993 | 86.435069996103 | | 1992 | 86.460755088825 | | 1991 | 86.64662174118 |
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