Year | Value | 2021 | 43.478260869565 | 2020 | 43.478260869565 | 2019 | 43.478260869565 | 2018 | 43.478260869565 | 2017 | 43.478260869565 | 2016 | 44.466403162055 | 2015 | 44.466403162055 | 2014 | 44.466403162055 | 2013 | 44.466403162055 | 2012 | 44.466403162055 | 2011 | 44.466403162055 | 2010 | 44.466403162055 | 2009 | 42.292490118577 | 2008 | 36.758893280632 | 2007 | 29.940711462451 | 2006 | 28.952569169961 | 2005 | 27.96442687747 | 2004 | 26.97628458498 | 2003 | 26.086956521739 | 2002 | 25.098814229249 | 2001 | 24.110671936759 | 2000 | 23.122529644269 | 1999 | 22.233201581028 | 1998 | 21.245059288538 | 1997 | 20.256916996047 | 1996 | 18.774703557312 | 1995 | 18.280632411067 | 1994 | 17.786561264822 | 1993 | 15.909090909091 | 1992 | 16.00790513834 | 1991 | 19.367588932806 | 1990 | 18.478260869565 | 1989 | 17.885375494071 | 1988 | 19.664031620553 | 1987 | 18.181818181818 | 1986 | 17.490118577075 | 1985 | 16.699604743083 | 1984 | 16.699604743083 | 1983 | 18.083003952569 | 1982 | 19.9604743083 | 1981 | 17.885375494071 | 1980 | 15.711462450593 | 1979 | 16.403162055336 | 1978 | 17.490118577075 | 1977 | 16.798418972332 | 1976 | 16.106719367589 | 1975 | 16.205533596838 | 1974 | 16.798418972332 | 1973 | 14.130434782609 | 1972 | 13.636363636364 | 1971 | 13.142292490119 | 1970 | 12.845849802372 | 1969 | 12.845849802372 | 1968 | 12.648221343873 | 1967 | 12.648221343873 | 1966 | 12.450592885375 | 1965 | 12.351778656127 | 1964 | 12.252964426878 | 1963 | 12.154150197628 | 1962 | 12.055335968379 | 1961 | 11.95652173913 |
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