Year | Value | 2021 | 3.19 | 2020 | 2.52 | 2019 | 2.85 | 2018 | 3.2 | 2017 | 4.39 | 2016 | 5.04 | 2015 | 5 | 2014 | 5.15 | 2013 | 5.66 | 2012 | 5.52 | 2011 | 6.79 | 2010 | 11.25 | 2009 | 10.69 | 2008 | 10.78 | 2007 | 10.8 | 2006 | 11.23 | 2005 | 11.91 | 2004 | 11.74 | 2003 | 12.75 | 2002 | 12.8 | 2001 | 12.79 | 2000 | 12.76 | 1999 | 12.46 | 1998 | 12.39 | 1997 | 12.36 | 1996 | 12.24 | 1995 | 13.81 | 1994 | 12.48 | 1992 | 12.02 | 1991 | 5.98 |
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