| Year | Value | | 2022 | 1.7573110203219 | | 2021 | 1.7721753668822 | | 2020 | 1.9226290397744 | | 2019 | 1.7048315444832 | | 2018 | 1.2217009742665 | | 2017 | 1.1042888369851 | | 2016 | 1.1160989371625 | | 2015 | 1.1095018688554 | | 2014 | 0.9848794290172 | | 2013 | 0.978618159746 | | 2012 | 1.0780828379572 | | 2011 | 1.0670627187426 | | 2010 | 1.2491829594517 | | 2009 | 1.5164866673441 | | 2008 | 1.4593850515874 | | 2007 | 1.4783889240077 | | 2006 | 1.5939980225837 | | 2005 | 1.6790905235989 | | 2004 | 1.6520060170675 | | 2003 | 1.8411110756344 | | 2002 | 1.7760268404571 | | 2001 | 1.8431609896201 | | 2000 | 1.6553123819075 | | 1999 | 1.5738265497392 | | 1998 | 1.7443365331593 | | 1997 | 2.2831162447776 | | 1996 | 2.9738286677448 | | 1995 | 3.1545581078747 | | 1994 | 1.9395190144639 | | 1993 | 1.9963603214656 |
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