Year | Value | 2022 | 2.224 | 2021 | 2.803 | 2020 | 2.551 | 2019 | 2.015 | 2018 | 2.246 | 2017 | 2.893 | 2016 | 3.952 | 2015 | 5.048 | 2014 | 6.108 | 2013 | 6.953 | 2012 | 6.979 | 2011 | 6.712 | 2010 | 7.281 | 2009 | 6.662 | 2008 | 4.393 | 2007 | 5.316 | 2006 | 7.141 | 2005 | 7.927 | 2004 | 8.298 | 2003 | 7.777 | 2002 | 7.281 | 2001 | 8.128 | 2000 | 8.764 | 1999 | 8.702 | 1998 | 6.455 | 1997 | 4.674 | 1996 | 3.852 | 1995 | 4.083 | 1994 | 4.284 | 1993 | 4.349 | 1992 | 2.6 | 1991 | 2.27 | 1990 | 0.7 |
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