Year | Value | 2022 | 7.178 | 2021 | 7.193 | 2020 | 8.102 | 2019 | 9.138 | 2018 | 9.881 | 2017 | 11.53 | 2016 | 12.3 | 2015 | 12.428 | 2014 | 13.533 | 2013 | 13.316 | 2012 | 12.723 | 2011 | 12.246 | 2010 | 12.193 | 2009 | 12.35 | 2008 | 12.748 | 2007 | 12.962 | 2006 | 13.055 | 2005 | 12.348 | 2004 | 11.921 | 2003 | 12.621 | 2002 | 12.992 | 2001 | 13.739 | 2000 | 14.427 | 1999 | 14.361 | 1998 | 15.078 | 1997 | 16.388 | 1996 | 16.153 | 1995 | 15.991 | 1994 | 15.431 | 1993 | 16.126 | 1992 | 16.443 | 1991 | 17.722 | 1990 | 18.662 | 1989 | 19.184 | 1988 | 19.821 | 1987 | 20.269 | 1986 | 20.617 | 1985 | 20.919 | 1984 | 21.183 | 1983 | 21.385 | 1982 | 21.476 | 1981 | 21.73 | 1980 | 21.931 | 1979 | 21.993 | 1978 | 21.92 | 1977 | 21.739 | 1976 | 21.485 | 1975 | 21.393 | 1974 | 21.382 |
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