Year | Value | 2022 | 8.806 | 2021 | 8.999 | 2020 | 9.182 | 2019 | 9.377 | 2018 | 9.662 | 2017 | 9.98 | 2016 | 10.26 | 2015 | 10.607 | 2014 | 11.004 | 2013 | 11.374 | 2012 | 11.754 | 2011 | 11.95 | 2010 | 11.926 | 2009 | 12.003 | 2008 | 12.249 | 2007 | 12.386 | 2006 | 12.472 | 2005 | 12.724 | 2004 | 12.698 | 2003 | 12.833 | 2002 | 12.919 | 2001 | 13.176 | 2000 | 13.526 | 1999 | 14.234 | 1998 | 15.578 | 1997 | 16.658 | 1996 | 17.253 | 1995 | 17.569 | 1994 | 18.238 | 1993 | 18.788 | 1992 | 19.215 | 1991 | 19.455 | 1990 | 19.728 | 1989 | 20.157 | 1988 | 20.295 | 1987 | 20.9 | 1986 | 21.584 | 1985 | 22.185 | 1984 | 22.896 | 1983 | 23.736 | 1982 | 24.786 | 1981 | 25.944 | 1980 | 26.766 | 1979 | 26.974 | 1978 | 27.579 | 1977 | 28.546 | 1976 | 29.758 | 1975 | 31.176 | 1974 | 32.421 |
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