| Year | Value | | 2020 | 1.0006857660054 | | 2019 | 0.99176919651655 | | 2018 | 0.99311447149595 | | 2017 | 1.0049912382441 | | 2016 | 1.0011904059073 | | 2015 | 1.0037032669812 | | 2014 | 1.0272493216487 | | 2013 | 1.0464345126723 | | 2012 | 1.0790249577876 | | 2011 | 1.1108897690413 | | 2010 | 1.1442950017524 | | 2009 | 1.1479161146823 | | 2008 | 1.1960875805822 | | 2007 | 1.2047776635723 | | 2006 | 1.2184664161399 | | 2005 | 1.2436239159341 | | 2004 | 1.2439972787733 | | 2003 | 1.2592296044461 | | 2002 | 1.290337214545 | | 2001 | 1.3513514001267 | | 2000 | 1.411763835766 | | 1999 | 1.5022906647746 | | 1998 | 1.6691918022085 | | 1997 | 1.7559489963439 | | 1996 | 1.8238682318498 | | 1995 | 1.8876962744788 | | 1994 | 1.9114129599012 | | 1993 | 1.9201634005927 | | 1992 | 1.9925916054864 | | 1991 | 2.0873724021408 |
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