Year | Value | 2022 | 49.893677648611 | 2021 | 49.877839058463 | 2020 | 49.858957273986 | 2019 | 49.835542361921 | 2018 | 49.811374230655 | 2017 | 49.785968656954 | 2016 | 49.774720452222 | 2015 | 49.780181750313 | 2014 | 49.796928415297 | 2013 | 49.818393878827 | 2012 | 49.835295534756 | 2011 | 49.855543791392 | 2010 | 49.876336267164 | 2009 | 49.898676667527 | 2008 | 49.921445445805 | 2007 | 49.947631417707 | 2006 | 49.98332261938 | 2005 | 50.028648537371 | 2004 | 50.089953397637 | 2003 | 50.16754378448 | 2002 | 50.248195641257 | 2001 | 50.321633099882 | 2000 | 50.365069042413 | 1999 | 50.382790395489 | 1998 | 50.399401135511 | 1997 | 50.395667623041 | 1996 | 50.371049608248 | 1995 | 50.34599701732 | 1994 | 50.319104440108 | 1993 | 50.292452971073 | 1992 | 50.265909206021 | 1991 | 50.236962757963 | 1990 | 50.206461518331 | 1989 | 50.176498251183 | 1988 | 50.14781566948 | 1987 | 50.118506628587 | 1986 | 50.086747563464 | 1985 | 50.053290277485 | 1984 | 50.019024136462 | 1983 | 49.983604513434 | 1982 | 49.946736503185 | 1981 | 49.908016242562 | 1980 | 49.868053549071 | 1979 | 49.827413625404 | 1978 | 49.786736704065 | 1977 | 49.74594768803 | 1976 | 49.705937291733 | 1975 | 49.668831199662 | 1974 | 49.634639176604 | 1973 | 49.952108040914 | 1972 | 50.297081632531 | 1971 | 50.308322507279 | 1970 | 50.323052007573 | 1969 | 50.340599760526 | 1968 | 50.361694154592 | 1967 | 50.41381026362 | 1966 | 50.469399508426 | 1965 | 50.501646906402 | 1964 | 50.538776775712 | 1963 | 50.580756991283 | 1962 | 50.627212944357 | 1961 | 50.679321566914 | 1960 | 50.738376781687 |
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