Year | Value | 2021 | 10.298333333333 | 2020 | 10.762803030303 | 2019 | 10.432413419913 | 2018 | 11.316558441558 | 2017 | 10.208874458875 | 2016 | 8.8311688311688 | 2015 | 10.647186147186 | 2014 | 8.6774891774892 | 2013 | 8.6287878787879 | 2012 | 9.2857142857143 | 2011 | 9.0909090909091 | 2010 | 8.9393939393939 | 2009 | 9.4047619047619 | 2008 | 8.9177489177489 | 2007 | 11.883116883117 | 2006 | 12.445887445887 | 2005 | 13.311688311688 | 2004 | 12.229437229437 | 2003 | 12.121212121212 | 2002 | 10.822510822511 | 2001 | 10.606060606061 | 2000 | 10.649350649351 | 1999 | 10.941558441558 | 1998 | 10.833333333333 | 1997 | 10.616883116883 | 1996 | 10.714285714286 | 1995 | 10.725108225108 | 1994 | 10.757575757576 | 1993 | 11.764069264069 | 1992 | 11.645021645022 | 1991 | 11.493506493506 | 1990 | 11.428571428571 | 1989 | 11.298701298701 | 1988 | 11.190476190476 | 1987 | 11.190476190476 | 1986 | 11.168831168831 | 1985 | 11.125541125541 | 1984 | 12.445887445887 | 1983 | 12.554112554113 | 1982 | 12.445887445887 | 1981 | 11.948051948052 | 1980 | 11.601731601732 | 1979 | 11.688311688312 | 1978 | 11.904761904762 | 1977 | 12.121212121212 | 1976 | 12.337662337662 | 1975 | 12.597402597403 | 1974 | 22.943722943723 | 1973 | 33.225108225108 | 1972 | 33.441558441558 | 1971 | 33.658008658009 | 1970 | 33.874458874459 | 1969 | 33.982683982684 | 1968 | 34.199134199134 | 1967 | 34.415584415584 | 1966 | 34.632034632035 | 1965 | 34.848484848485 | 1964 | 34.95670995671 | 1963 | 35.17316017316 | 1962 | 35.38961038961 | 1961 | 35.606060606061 |
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