| Year | Value | | 2021 | 1.8894830659536 | | 2020 | 1.8894830659536 | | 2019 | 1.8894830659536 | | 2018 | 1.9251336898396 | | 2017 | 1.9251336898396 | | 2016 | 1.9251336898396 | | 2015 | 1.9251336898396 | | 2014 | 1.9251336898396 | | 2013 | 1.9251336898396 | | 2012 | 1.9251336898396 | | 2011 | 1.9251336898396 | | 2010 | 1.9251336898396 | | 2009 | 1.9251336898396 | | 2008 | 1.6399286987522 | | 2007 | 1.4616755793226 | | 2006 | 1.4616755793226 | | 2005 | 1.319073083779 | | 2004 | 1.319073083779 | | 2003 | 1.319073083779 | | 2002 | 1.319073083779 | | 2001 | 1.0695187165775 | | 2000 | 0.7843137254902 | | 1999 | 0.71301247771836 | | 1998 | 0.71301247771836 | | 1997 | 0.67736185383244 | | 1996 | 0.64171122994652 | | 1995 | 0.60606060606061 | | 1994 | 0.60606060606061 | | 1993 | 0.60606060606061 | | 1992 | 0.60606060606061 | | 1991 | 0.57040998217469 | | 1990 | 0.57040998217469 | | 1989 | 0.53475935828877 | | 1988 | 0.53475935828877 | | 1987 | 0.53475935828877 | | 1986 | 0.53475935828877 | | 1985 | 0.53475935828877 | | 1984 | 0.53475935828877 | | 1983 | 0.53475935828877 | | 1982 | 0.57040998217469 | | 1981 | 0.64171122994652 | | 1980 | 0.67736185383244 | | 1979 | 0.74866310160428 | | 1978 | 0.7843137254902 | | 1977 | 0.85561497326203 | | 1976 | 0.89126559714795 | | 1975 | 0.96256684491979 | | 1974 | 0.9982174688057 | | 1973 | 1.0695187165775 | | 1972 | 1.1051693404635 | | 1971 | 1.0338680926916 | | 1970 | 1.0695187165775 | | 1969 | 1.1408199643494 | | 1968 | 1.1764705882353 | | 1967 | 1.2477718360071 | | 1966 | 1.283422459893 | | 1965 | 1.3547237076649 | | 1964 | 1.3903743315508 | | 1963 | 1.4616755793226 | | 1962 | 1.4973262032086 | | 1961 | 1.5686274509804 |
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