| Year | Value | | 2022 | 0.44781644121254 | | 2021 | 0.57753593534637 | | 2020 | 0.79067228253556 | | 2019 | 0.85061426333231 | | 2018 | 0.59479308091298 | | 2017 | 0.46697788415733 | | 2016 | 0.097086000115959 | | 2015 | 0.91263243030182 | | 2014 | 0.79890431426029 | | 2013 | 0.10021277897927 | | 2012 | 0.21216312543202 | | 2011 | 0.018909503536408 | | 2010 | 0.046531242205847 | | 2009 | 0.0072690795196723 | | 2008 | 0.010177599113142 | | 2007 | 0.047994067109434 | | 2006 | 0.098969560386678 | | 2005 | 0.14572163921611 | | 2004 | 0.19267828697001 | | 2003 | 0.26334284881813 | | 2002 | 0.15980650690484 | | 2001 | 0.28278614292439 | | 2000 | 0.51370475771948 | | 1999 | 0.34874632109035 | | 1998 | 0.20721792096637 | | 1997 | 0.12296832583832 | | 1996 | 0.050590098428783 | | 1995 | 0.0043352914406372 | | 1994 | 0.041917509846465 | | 1993 | 0.082440831680904 | | 1992 | 0.041952073988031 | | 1991 | 0.49054361038408 | | 1990 | 0.7084701501213 | | 1989 | 0.60126132181293 | | 1988 | 0.58213400469295 | | 1987 | 0.57314817199737 | | 1986 | 0.5335736097704 | | 1985 | 0.47376283469177 | | 1984 | 0.46184333678479 | | 1983 | 0.49277162414263 | | 1982 | 0.42045157365127 | | 1981 | 0.063052568739606 | | 1980 | 0.28817277362835 | | 1979 | 0.39932305930481 | | 1978 | 0.4646668573677 | | 1977 | 0.54764192745781 | | 1976 | 0.62636522665176 | | 1975 | 0.67266405252538 | | 1974 | 0.69143634589761 | | 1973 | 0.66189508716609 | | 1972 | 0.63173217991773 | | 1971 | 0.77354443193157 | | 1970 | 1.2972965391368 | | 1969 | 1.6934979729738 | | 1968 | 1.6663910576835 | | 1967 | 1.5817876242386 | | 1966 | 1.5318812543405 | | 1965 | 1.4235509421437 | | 1964 | 1.3005292453954 | | 1963 | 1.3094990579123 | | 1962 | 1.3632949450378 | | 1961 | 1.6965691550534 |
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