| Year | Value | | 2021 | 36.612441053482 | | 2020 | 36.256930357006 | | 2019 | 36.258971977353 | | 2018 | 36.261014149787 | | 2017 | 36.263055770134 | | 2016 | 36.281660573827 | | 2015 | 36.283850705767 | | 2014 | 36.270948416016 | | 2013 | 36.258046126265 | | 2012 | 36.245143836515 | | 2011 | 36.232241546764 | | 2010 | 36.219339257014 | | 2009 | 36.193367726189 | | 2008 | 36.167396195365 | | 2007 | 36.112515614343 | | 2006 | 36.086564857804 | | 2005 | 36.060614101266 | | 2004 | 36.034663344727 | | 2003 | 36.008712588189 | | 2002 | 35.98276183165 | | 2001 | 35.956811075112 | | 2000 | 35.930860318573 | | 1999 | 35.93333492969 | | 1998 | 35.929941531412 | | 1997 | 35.926548133134 | | 1996 | 35.923154734857 | | 1995 | 35.919761336579 | | 1994 | 35.916367938301 | | 1993 | 35.912974540023 | | 1992 | 35.909581141745 | | 1991 | 35.906187743467 | | 1990 | 35.90279434519 |
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