Year | Value | 2022 | 8.4 | 2021 | 11.3 | 2020 | 5.3 | 2019 | 10.8 | 2018 | 10.9 | 2017 | 11 | 2016 | 10.6 | 2015 | 9.3 | 2014 | 8.6 | 2013 | 9.5 | 2012 | 10.6 | 2011 | 12 | 2009 | 14.6 | 2008 | 15.7 | 2007 | 18 | 2006 | 19.4 | 2005 | 22.3 | 2004 | 24.4 | 2003 | 26.1 | 2002 | 25.3 | 2001 | 26.2 | 1999 | 29.9 | 1998 | 28.9 | 1997 | 30.2 | 1996 | 30 | 1995 | 29.7 | 1993 | 39.7 | 1992 | 40.7 | 1990 | 41.6 | 1989 | 36.4 | 1988 | 39.3 | 1987 | 36.5 | 1986 | 26.1 | 1985 | 45.2 | 1984 | 50.1 | 1983 | 50.9 | 1982 | 43 | 1981 | 42.9 |
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