Year | Value | 2023 | 7.456 | 2022 | 7.544 | 2021 | 8.327 | 2020 | 8.033 | 2019 | 7.797 | 2018 | 7.83 | 2017 | 7.921 | 2016 | 8.007 | 2015 | 8.162 | 2014 | 8.28 | 2013 | 8.359 | 2012 | 8.484 | 2011 | 8.612 | 2010 | 8.85 | 2009 | 8.997 | 2008 | 9.233 | 2007 | 9.449 | 2006 | 9.641 | 2005 | 9.88 | 2004 | 10.108 | 2003 | 10.133 | 2002 | 10.171 | 2001 | 10.307 | 2000 | 10.692 | 1999 | 10.76 | 1998 | 10.814 | 1997 | 10.946 | 1996 | 11.024 | 1995 | 11.17 | 1994 | 11.684 | 1993 | 11.393 | 1992 | 12.762 | 1991 | 11.575 | 1990 | 11.189 | 1989 | 11.391 | 1988 | 11.704 | 1987 | 11.872 | 1986 | 12.109 | 1985 | 12.428 | 1984 | 12.718 | 1983 | 13.042 | 1982 | 13.341 | 1981 | 13.659 | 1980 | 13.794 | 1979 | 14.004 | 1978 | 14.217 | 1977 | 14.485 | 1976 | 14.818 | 1975 | 15.199 |
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