Year | Value | 2022 | 25.2 | 2021 | 28.4 | 2020 | 27.6 | 2019 | 27.2 | 2018 | 27.9 | 2017 | 28.4 | 2016 | 29 | 2015 | 29.2 | 2014 | 30.7 | 2013 | 31.2 | 2012 | 32.3 | 2011 | 33.6 | 2010 | 35.6 | 2009 | 37.6 | 2008 | 38 | 2007 | 40 | 2006 | 41.9 | 2005 | 45.7 | 2004 | 48.3 | 2003 | 49.8 | 2002 | 50.3 | 2001 | 50.4 | 2000 | 50.8 | 1999 | 53.2 | 1998 | 52.2 | 1997 | 52.9 | 1996 | 53.9 | 1995 | 53.1 | 1994 | 53.2 | 1993 | 55.4 | 1992 | 55.5 | 1991 | 54.9 | 1990 | 55.3 | 1989 | 53.4 | 1988 | 53.9 | 1987 | 53.3 | 1986 | 50 | 1985 | 56.5 | 1984 | 58 | 1983 | 58.2 | 1982 | 54.8 | 1981 | 54.4 |
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