| Year | Value | | 2021 | 0.97752821760233 | | 2020 | 0.97752821760233 | | 2019 | 0.97752821760233 | | 2018 | 0.97752821760233 | | 2017 | 0.97752821760233 | | 2016 | 0.97752821760233 | | 2015 | 0.97752821760233 | | 2014 | 0.97752821760233 | | 2013 | 0.97752821760233 | | 2012 | 0.97752821760233 | | 2011 | 0.97525489616604 | | 2010 | 0.97525489616604 | | 2009 | 0.99457812837446 | | 2008 | 0.99457812837446 | | 2007 | 0.99457812837446 | | 2006 | 0.99457812837446 | | 2005 | 0.99457812837446 | | 2004 | 0.99457812837446 | | 2003 | 1.0315196017141 | | 2002 | 1.0315196017141 | | 2001 | 1.0315196017141 | | 2000 | 1.0315196017141 | | 1999 | 1.0315196017141 | | 1998 | 1.0315196017141 | | 1997 | 1.1525739681962 | | 1996 | 1.1525739681962 | | 1995 | 1.062777771463 | | 1994 | 1.0372029053048 | | 1993 | 1.0315196017141 | | 1992 | 1.0315196017141 | | 1991 | 1.0286779499187 | | 1990 | 1.0258362981234 | | 1989 | 1.0258362981234 | | 1988 | 1.022994646328 | | 1987 | 1.022994646328 | | 1986 | 1.0201529945327 | | 1985 | 1.0156063516601 | | 1984 | 1.0116280391466 | | 1983 | 1.0087863873512 | | 1982 | 1.0031030837605 | | 1981 | 0.99912477124703 | | 1980 | 0.99628311945168 | | 1979 | 0.99457812837446 | | 1978 | 0.99457812837446 | | 1977 | 0.99173647657911 | | 1976 | 0.98889482478375 | | 1975 | 0.98889482478375 | | 1974 | 0.9860531729884 | | 1973 | 0.9860531729884 | | 1972 | 0.98321152119304 | | 1971 | 0.98321152119304 | | 1970 | 0.98036986939768 | | 1969 | 0.98036986939768 | | 1968 | 0.98036986939768 | | 1967 | 0.97752821760233 | | 1966 | 0.97752821760233 | | 1965 | 0.97468656580697 | | 1964 | 0.97468656580697 | | 1963 | 0.97184491401162 | | 1962 | 0.97184491401162 | | 1961 | 0.9661616104209 |
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