Year | Value | 2022 | 22.7 | 2021 | 23.7 | 2020 | 24.3 | 2019 | 23.4 | 2018 | 24.7 | 2017 | 26.6 | 2016 | 27.9 | 2015 | 28.6 | 2014 | 29.6 | 2013 | 30.5 | 2012 | 32.6 | 2011 | 34 | 2010 | 36.2 | 2009 | 38.3 | 2008 | 39.7 | 2007 | 40.8 | 2006 | 42.5 | 2005 | 43.9 | 2004 | 45.7 | 2003 | 47.5 | 2002 | 48.8 | 2001 | 50.3 | 2000 | 51.2 | 1999 | 52.4 | 1998 | 52.6 | 1997 | 52.6 | 1996 | 53.2 | 1995 | 54.1 | 1994 | 55.1 | 1993 | 55.8 | 1992 | 56.1 | 1991 | 56.5 | 1990 | 56.6 | 1989 | 56.6 | 1988 | 56.1 | 1987 | 56.8 | 1986 | 56.8 | 1985 | 57.6 | 1984 | 58 | 1983 | 58.2 | 1982 | 58.1 | 1981 | 58 |
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