Year | Value | 2021 | 11.05 | 2020 | 10.759 | 2019 | 10.531 | 2018 | 10.584 | 2017 | 11.01 | 2016 | 11.01 | 2015 | 11.072 | 2014 | 11.493 | 2013 | 11.136 | 2012 | 11.104 | 2011 | 11.6 | 2010 | 11.68 | 2009 | 12.221 | 2008 | 12.465 | 2007 | 12.916 | 2006 | 13.533 | 2005 | 14.028 | 2004 | 14.651 | 2003 | 15.309 | 2002 | 17.226 | 2001 | 17.833 | 2000 | 18.587 | 1999 | 20.606 | 1998 | 55.947 | 1997 | 30.951 | 1996 | 32.204 | 1995 | 32.71 | 1994 | 20.98 | 1993 | 45.732 | 1992 | 45.705 | 1991 | 33.899 | 1990 | 34.067 | 1989 | 33.879 | 1988 | 74.552 | 1987 | 47.475 | 1986 | 30.275 | 1985 | 30.611 | 1984 | 30.857 | 1983 | 27.813 | 1982 | 24.553 | 1981 | 24.919 | 1980 | 25.328 | 1979 | 25.861 | 1978 | 26.198 | 1977 | 26.576 | 1976 | 27.1 | 1975 | 27.254 | 1974 | 27.52 | 1973 | 27.571 | 1972 | 32.361 | 1971 | 32.737 | 1970 | 39.927 | 1969 | 40.5 | 1968 | 39.551 | 1967 | 40.076 | 1966 | 40.669 | 1965 | 35.94 | 1964 | 31.209 | 1963 | 36.509 | 1962 | 35.629 | 1961 | 35.935 | 1960 | 36.098 |
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