| Year | Value | | 2020 | 1.0439533595046 | | 2019 | 0.97353844620149 | | 2018 | 0.98199738267636 | | 2017 | 1.0544803605142 | | 2016 | 0.97231107587081 | | 2015 | 1.0139153147422 | | 2014 | 1.0699719014016 | | 2013 | 1.1138343649444 | | 2012 | 1.2153870147191 | | 2011 | 1.337221136141 | | 2010 | 1.4519476013954 | | 2009 | 1.5460835514497 | | 2008 | 1.6742834430838 | | 2007 | 1.7801168685422 | | 2006 | 1.8916900523422 | | 2005 | 2.0052292892508 | | 2004 | 1.926034762176 | | 2003 | 2.1215361841916 | | 2002 | 2.2215297393472 | | 2001 | 2.1564329023273 | | 2000 | 2.2312694274321 | | 1999 | 2.3264102572918 | | 1998 | 2.4199480009203 | | 1997 | 2.5117047917883 | | 1996 | 2.6661710323081 | | 1995 | 2.870740903672 | | 1994 | 2.0679472315012 | | 1993 | 1.7360181818971 | | 1992 | 1.8321981339062 | | 1991 | 1.8551774291693 |
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