| Year | Value | | 2022 | 84.843235939572 | | 2021 | 84.020815825709 | | 2020 | 83.324528461747 | | 2019 | 83.157962479638 | | 2018 | 83.362103915983 | | 2017 | 82.800708008565 | | 2016 | 82.250442987796 | | 2015 | 81.59773178244 | | 2014 | 80.275916657091 | | 2013 | 78.085435226318 | | 2012 | 77.933306927283 | | 2011 | 78.485239757107 | | 2010 | 76.880915065151 | | 2009 | 75.970940953393 | | 2008 | 75.681527047974 | | 2007 | 75.221689556448 | | 2006 | 75.313915547327 | | 2005 | 74.18817691448 | | 2004 | 73.883707420371 | | 2003 | 72.68598001683 | | 2002 | 72.472868345715 | | 2001 | 72.106912813547 | | 2000 | 73.677438689178 | | 1999 | 72.823434163402 | | 1998 | 71.42917261825 | | 1997 | 71.609985096509 | | 1996 | 71.589123322544 | | 1995 | 72.255852622015 | | 1994 | 72.681818822214 | | 1993 | 74.153149455118 | | 1992 | 74.394701410906 | | 1991 | 74.270667623883 |
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