Year | Value | 2022 | 1.7 | 2021 | 1.8 | 2020 | 2.1 | 2019 | 2 | 2018 | 2.1 | 2017 | 2.7 | 2016 | 2.7 | 2015 | 3.2 | 2014 | 3.5 | 2013 | 3.3 | 2012 | 3.8 | 2011 | 4.2 | 2010 | 4.8 | 2009 | 5.2 | 2008 | 5.9 | 2007 | 7.8 | 2006 | 9.9 | 2005 | 12.3 | 2004 | 13.4 | 2003 | 16.1 | 2002 | 17 | 2001 | 19.2 | 2000 | 21.4 | 1999 | 24.6 | 1998 | 19.2 | 1997 | 18.5 | 1996 | 20.6 | 1995 | 19.4 | 1994 | 21.3 | 1993 | 17.7 | 1992 | 15.4 | 1991 | 12.9 | 1990 | 11.6 |
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