| Year | Value | | 2021 | 13.158436257966 | | 2020 | 13.158436257966 | | 2019 | 13.158436257966 | | 2018 | 13.158436257966 | | 2017 | 13.158436257966 | | 2016 | 13.158436257966 | | 2015 | 13.158436257966 | | 2014 | 13.158436257966 | | 2013 | 13.158436257966 | | 2012 | 13.158436257966 | | 2011 | 13.158436257966 | | 2010 | 13.158436257966 | | 2009 | 13.158436257966 | | 2008 | 13.158436257966 | | 2007 | 13.155844457172 | | 2006 | 13.157370919309 | | 2005 | 13.166159892415 | | 2004 | 13.184602133051 | | 2003 | 13.202934134588 | | 2002 | 13.22579778694 | | 2001 | 13.239021662422 | | 2000 | 13.256668868359 | | 1999 | 13.228170224139 | | 1998 | 13.264331890631 | | 1997 | 13.30933868176 | | 1996 | 13.195233105955 | | 1995 | 13.212539945953 | | 1994 | 13.29019072322 | | 1993 | 13.352410384849 | | 1992 | 13.522371941342 |
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