| Year | Value | | 2021 | 40.05615640599 | | 2020 | 40.05615640599 | | 2019 | 40.05615640599 | | 2018 | 40.05615640599 | | 2017 | 40.05615640599 | | 2016 | 40.003535773711 | | 2015 | 39.96817936026 | | 2014 | 39.953868552413 | | 2013 | 39.93125103976 | | 2012 | 39.915280319414 | | 2011 | 39.899309599068 | | 2010 | 39.88085088686 | | 2009 | 39.847369515492 | | 2008 | 39.804781704782 | | 2007 | 39.770478170478 | | 2006 | 39.736174636175 | | 2005 | 39.701871101871 | | 2004 | 39.667567567568 | | 2003 | 39.625025982124 | | 2002 | 39.598960498961 | | 2001 | 39.564656964657 | | 2000 | 39.530353430353 | | 1999 | 39.532577962578 | | 1998 | 39.534802494802 | | 1997 | 39.537027027027 | | 1996 | 39.539251559252 | | 1995 | 39.541476091476 | | 1994 | 39.543700623701 | | 1993 | 39.545925155925 |
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