| Year | Value | | 2021 | 72.106261859583 | | 2020 | 72.106261859583 | | 2019 | 72.106261859583 | | 2018 | 72.106261859583 | | 2017 | 72.106261859583 | | 2016 | 72.106261859583 | | 2015 | 72.106261859583 | | 2014 | 72.106261859583 | | 2013 | 72.106261859583 | | 2012 | 72.106261859583 | | 2011 | 72.106261859583 | | 2010 | 72.106261859583 | | 2009 | 72.428842504744 | | 2008 | 72.751423149905 | | 2007 | 73.074003795066 | | 2006 | 73.396584440228 | | 2005 | 73.719165085389 | | 2004 | 74.04174573055 | | 2003 | 74.364326375712 | | 2002 | 74.686907020873 | | 2001 | 75.009487666034 | | 2000 | 75.332068311195 | | 1999 | 75.635673624288 | | 1998 | 75.939278937381 | | 1997 | 76.242884250474 | | 1996 | 76.546489563567 | | 1995 | 76.85009487666 | | 1994 | 77.153700189753 | | 1993 | 77.457305502846 | | 1992 | 77.760910815939 | | 1991 | 78.064516129032 | | 1990 | 78.368121442125 |
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