Year | Value | 2022 | 23.5 | 2021 | 28.4 | 2020 | 18.7 | 2019 | 26.2 | 2018 | 26.7 | 2017 | 27.1 | 2016 | 27 | 2015 | 25.3 | 2014 | 24.3 | 2013 | 25.7 | 2012 | 28.2 | 2011 | 29.9 | 2009 | 33.8 | 2008 | 35.8 | 2007 | 39 | 2006 | 41.4 | 2005 | 45 | 2004 | 47.3 | 2003 | 48.7 | 2002 | 47.3 | 2001 | 48 | 1999 | 53.8 | 1998 | 52 | 1997 | 53 | 1996 | 52.6 | 1995 | 52.6 | 1993 | 64.3 | 1992 | 65.4 | 1990 | 63.7 | 1989 | 58.3 | 1988 | 61.4 | 1987 | 59.2 | 1986 | 49.5 | 1985 | 68 | 1984 | 72.2 | 1983 | 72.1 | 1982 | 66.4 | 1981 | 67 |
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