Year | Value | 2022 | 12.917 | 2021 | 14.781 | 2020 | 15.532 | 2019 | 14.104 | 2018 | 15.255 | 2017 | 17.224 | 2016 | 19.635 | 2015 | 22.058 | 2014 | 24.442 | 2013 | 26.094 | 2012 | 24.788 | 2011 | 21.391 | 2010 | 19.86 | 2009 | 17.857 | 2008 | 11.255 | 2007 | 8.232 | 2006 | 8.452 | 2005 | 9.146 | 2004 | 11.09 | 2003 | 11.283 | 2002 | 11.146 | 2001 | 10.348 | 2000 | 13.785 | 1999 | 15.475 | 1998 | 18.673 | 1997 | 20.698 | 1996 | 22.142 | 1995 | 22.675 | 1994 | 24.209 | 1993 | 22.156 | 1992 | 17.697 | 1991 | 18.88 | 1990 | 16.273 | 1989 | 17.331 | 1988 | 19.854 | 1987 | 20.607 | 1986 | 21.259 | 1985 | 21.64 | 1984 | 20.25 | 1983 | 17.49 | 1982 | 16 | 1981 | 14.17 | 1980 | 11.4 | 1979 | 8.61 | 1978 | 6.97 | 1977 | 5.2 | 1976 | 2.9 | 1975 | 4.8 | 1974 | 3.04 | 1973 | 2.49 | 1972 | 1.5 | 1971 | 1.5 | 1970 | 1.1 | 1969 | 1.3 |
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