| Year | Value | | 2022 | 1.187986015195 | | 2021 | 1.2354412382521 | | 2020 | 1.0591092134635 | | 2019 | 1.0543316103123 | | 2018 | 0.97785679028147 | | 2017 | 0.98178063752587 | | 2016 | 1.0042870781767 | | 2015 | 0.93011953162391 | | 2014 | 0.97373958819678 | | 2013 | 1.0469482555709 | | 2012 | 1.1667912335424 | | 2011 | 1.2921707637493 | | 2010 | 1.6031252117881 | | 2009 | 1.5861568246702 | | 2008 | 1.4929191411375 | | 2007 | 1.4429145423496 | | 2006 | 1.542182212926 | | 2005 | 1.4201971624414 | | 2004 | 1.4306519446502 | | 2003 | 1.4037983371061 | | 2002 | 1.3876185755664 | | 2001 | 1.3004824737298 | | 2000 | 1.0931662754363 | | 1999 | 1.211302468275 | | 1998 | 1.3611824689973 | | 1997 | 1.4013683175191 | | 1996 | 1.5363628120904 | | 1995 | 1.5730347757492 | | 1994 | 1.6540746622661 | | 1993 | 1.8173013500764 | | 1992 | 2.2472333323132 |
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