| Year | Value | | 2020 | 0.77314204710156 | | 2019 | 0.76955901991998 | | 2018 | 0.77476458614367 | | 2017 | 0.77904154409106 | | 2016 | 0.77756003645819 | | 2015 | 0.78167955994434 | | 2014 | 0.78612223297519 | | 2013 | 0.79094139864692 | | 2012 | 0.79595550732906 | | 2011 | 0.8012968051103 | | 2010 | 0.92256441275967 | | 2009 | 0.93139365879429 | | 2008 | 0.95265392329348 | | 2007 | 0.98027611836798 | | 2006 | 1.0035114227475 | | 2005 | 1.2741919856604 | | 2004 | 1.2607026010205 | | 2003 | 1.2939422731457 | | 2002 | 1.2337747200474 | | 2001 | 1.2950392633554 | | 2000 | 1.2987096890731 | | 1999 | 1.3231819901607 | | 1998 | 1.1790263321583 | | 1997 | 0.9096347176205 | | 1996 | 0.9659453064912 | | 1995 | 0.95623694961183 | | 1994 | 0.22768488866778 | | 1993 | 0.1885301286228 |
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