Year | Value | 2021 | 11.143 | 2020 | 11.181 | 2019 | 11.443 | 2018 | 12.094 | 2017 | 12.615 | 2016 | 12.848 | 2015 | 13.614 | 2014 | 14.95 | 2013 | 17.061 | 2012 | 16.399 | 2011 | 16.312 | 2010 | 19.855 | 2009 | 19.988 | 2008 | 19.859 | 2007 | 18.673 | 2006 | 18.679 | 2005 | 19.488 | 2004 | 17.781 | 2003 | 15.749 | 2002 | 16.858 | 2001 | 17.249 | 2000 | 17.329 | 1999 | 19.096 | 1998 | 21.392 | 1997 | 21.049 | 1996 | 21.125 | 1995 | 20.894 | 1994 | 20.639 | 1993 | 21.327 | 1992 | 22.173 | 1991 | 26.355 | 1990 | 27.647 | 1989 | 27.29 | 1988 | 29.114 | 1987 | 27.325 | 1986 | 30.03 | 1985 | 30.841 | 1984 | 32.649 | 1983 | 32.871 | 1982 | 33.241 | 1981 | 31.247 | 1980 | 33.82 | 1979 | 31.204 | 1978 | 32.263 | 1977 | 33.764 | 1976 | 35.508 | 1975 | 35.413 | 1974 | 36.686 | 1973 | 36.447 | 1972 | 37.631 | 1971 | 37.803 | 1970 | 36.677 | 1969 | 38.419 | 1968 | 37.705 | 1967 | 37.772 | 1966 | 37.501 | 1965 | 38.466 | 1964 | 39.515 | 1963 | 40.43 | 1962 | 40.708 | 1961 | 40.947 | 1960 | 41.129 |
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