Year | Value | 2023 | 7.151 | 2022 | 6.719 | 2021 | 7.617 | 2020 | 7.759 | 2019 | 6.695 | 2018 | 7.361 | 2017 | 8.64 | 2016 | 8.818 | 2015 | 9.376 | 2014 | 8.663 | 2013 | 8.193 | 2012 | 7.689 | 2011 | 7.781 | 2010 | 8.394 | 2009 | 8.25 | 2008 | 6.369 | 2007 | 6.854 | 2006 | 8.935 | 2005 | 9.602 | 2004 | 10.358 | 2003 | 10.469 | 2002 | 10.423 | 2001 | 10.291 | 2000 | 11.135 | 1999 | 11.693 | 1998 | 13.215 | 1997 | 14.968 | 1996 | 15.572 | 1995 | 17.005 | 1994 | 16.426 | 1993 | 16.201 | 1992 | 11.595 | 1991 | 6.503 | 1990 | 3.069 | 1989 | 3.14 | 1988 | 4.47 | 1987 | 5.07 | 1986 | 5.32 | 1985 | 5 | 1984 | 5.12 | 1983 | 5.43 | 1982 | 5.28 | 1981 | 5.04 | 1980 | 4.86 | 1979 | 6.2 | 1978 | 7.23 | 1977 | 6.09 | 1976 | 3.75 | 1975 | 2.08 | 1974 | 1.61 |
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