| Year | Value | | 2020 | 0.97366717135082 | | 2019 | 0.84235637402645 | | 2018 | 0.84304565706513 | | 2017 | 0.85318899650683 | | 2016 | 0.85561938781938 | | 2015 | 0.8393067631339 | | 2014 | 0.85402836305833 | | 2013 | 0.8763685291281 | | 2012 | 0.8833677005434 | | 2011 | 0.89322503888429 | | 2010 | 0.80457729974023 | | 2009 | 0.97595240702181 | | 2008 | 0.86531389261455 | | 2007 | 0.85908119640755 | | 2006 | 1.0177754482029 | | 2005 | 1.0297458470233 | | 2004 | 1.094435769587 | | 2003 | 1.1211573750158 | | 2002 | 1.1400418785004 | | 2001 | 1.1511764397051 | | 2000 | 1.3802329154985 | | 1999 | 1.5627287744768 | | 1998 | 1.7359957492624 | | 1997 | 1.8470014766042 | | 1996 | 1.9208619628258 | | 1995 | 1.7586178901548 | | 1994 | 1.4211631083111 | | 1993 | 1.4955393812332 | | 1992 | 1.7327103277088 | | 1991 | 1.9400584381281 |
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