Year | Value | 2022 | 10.9 | 2021 | 11.4 | 2020 | 15.4 | 2019 | 12 | 2018 | 10.4 | 2017 | 8.2 | 2016 | 9.2 | 2014 | 9.5 | 2013 | 8.6 | 2012 | 8.6 | 2011 | 9.1 | 2010 | 11.4 | 2009 | 12.9 | 2008 | 14.2 | 2007 | 15.6 | 2006 | 16.9 | 2005 | 21 | 2004 | 24.9 | 2003 | 29.7 | 2002 | 44.4 | 2001 | 31.1 | 2000 | 26.3 | 1999 | 24.2 | 1998 | 23.3 | 1997 | 21.3 | 1996 | 22.4 | 1995 | 20.5 | 1994 | 15.7 | 1993 | 15.1 | 1992 | 14.9 | 1991 | 14.3 | 1987 | 7.6 | 1986 | 4.8 | 1980 | 5.5 |
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