| Year | Value | | 2021 | 43.059636992221 | | 2020 | 43.059636992221 | | 2019 | 43.059636992221 | | 2018 | 43.059636992221 | | 2017 | 43.059636992221 | | 2016 | 43.059636992221 | | 2015 | 43.059636992221 | | 2014 | 43.059636992221 | | 2013 | 43.059636992221 | | 2012 | 43.059636992221 | | 2011 | 43.059636992221 | | 2010 | 43.059636992221 | | 2009 | 43.033419763757 | | 2008 | 43.007202535292 | | 2007 | 42.980985306828 | | 2006 | 42.954768078364 | | 2005 | 42.928550849899 | | 2004 | 42.902333621435 | | 2003 | 42.87611639297 | | 2002 | 42.849899164506 | | 2001 | 42.823681936042 | | 2000 | 42.797464707577 | | 1999 | 40.474863387978 | | 1998 | 40.362295081967 | | 1997 | 40.249726775956 | | 1996 | 40.137158469945 | | 1995 | 40.024590163934 | | 1994 | 39.912021857923 | | 1993 | 39.799453551913 | | 1992 | 39.686885245902 | | 1991 | 39.574316939891 | | 1990 | 39.46174863388 |
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