| Year | Value | | 2021 | 0.8425673008605 | | 2020 | 0.85237230599195 | | 2019 | 0.86217731112339 | | 2018 | 0.87198231625484 | | 2017 | 0.88178732138628 | | 2016 | 0.89159232651772 | | 2015 | 0.90139733164917 | | 2014 | 0.91120233678061 | | 2013 | 0.92100734191206 | | 2012 | 0.9308123470435 | | 2011 | 0.94061735217494 | | 2010 | 0.95042235730639 | | 2009 | 0.96022736243783 | | 2008 | 0.97003236756927 | | 2007 | 0.97983737270072 | | 2006 | 0.98964237783216 | | 2005 | 0.99944738296361 | | 2004 | 1.009252388095 | | 2003 | 1.0190573932265 | | 2002 | 1.0288623983579 | | 2001 | 1.0386674034894 | | 2000 | 1.0484724086208 | | 1999 | 1.0971737585853 | | 1998 | 1.1458751085498 | | 1997 | 1.1945764585142 | | 1996 | 1.2432778084787 | | 1995 | 1.2919791584432 | | 1994 | 1.3406805084077 | | 1993 | 1.3893818583722 | | 1992 | 1.4380832083366 | | 1991 | 1.4867845583011 | | 1990 | 1.5354859082656 |
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