Year | Value | 2022 | 8.6376004324529 | 2021 | 6.1898820829598 | 2020 | 8.0751450064752 | 2019 | 14.013863161391 | 2018 | 15.068006096839 | 2017 | 14.022317899356 | 2016 | 13.045238745588 | 2015 | 13.907786458162 | 2014 | 12.946381511637 | 2013 | 14.42427100155 | 2012 | 17.165108444453 | 2011 | 12.297437904376 | 2010 | 16.018051380417 | 2009 | 14.845630129728 | 2008 | 18.892536950194 | 2007 | 25.102392098528 | 2006 | 20.589663324695 | 2005 | 18.285891208717 | 2004 | 23.105275969597 | 2003 | 25.963057978543 | 2002 | 27.608548832935 | 2001 | 28.684029007145 | 2000 | 26.869107037111 | 1999 | 25.62323753579 | 1998 | 26.587273838104 | 1997 | 27.128496664395 | 1996 | 25.617388684113 | 1995 | 25.193284771457 | 1994 | 25.247772491563 | 1993 | 27.717978181792 | 1992 | 29.060902778306 | 1991 | 27.58217969971 | 1990 | 25.821501096478 | 1989 | 26.377952832305 | 1988 | 28.386152076143 | 1987 | 29.052101488714 | 1986 | 28.365482147432 | 1985 | 20.78469122472 | 1984 | 17.130919152539 | 1983 | 15.709472694627 | 1982 | 14.353944563024 | 1981 | 12.361641746901 | 1980 | 10.405887173548 | 1979 | 19.188481616779 | 1978 | 19.143496324951 | 1977 | 20.580668790404 | 1976 | 25.765306122602 |
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