Year | Value | 2022 | 47.762107789572 | 2021 | 47.811995901016 | 2020 | 47.852368311639 | 2019 | 47.888678233228 | 2018 | 47.935586928287 | 2017 | 47.990326299434 | 2016 | 48.043315756511 | 2015 | 48.091531129599 | 2014 | 48.135460808828 | 2013 | 48.180215221055 | 2012 | 48.225545135463 | 2011 | 48.274374917317 | 2010 | 48.339548640134 | 2009 | 48.40391569784 | 2008 | 48.464008599898 | 2007 | 48.530192973333 | 2006 | 48.591010139963 | 2005 | 48.641188715483 | 2004 | 48.688241243526 | 2003 | 48.738515170315 | 2002 | 48.78713301118 | 2001 | 48.832312985019 | 2000 | 48.883740392721 | 1999 | 48.927786381576 | 1998 | 48.957824716707 | 1997 | 48.990718023284 | 1996 | 49.024211876052 | 1995 | 49.055929815659 | 1994 | 49.085194746885 | 1993 | 49.113005094321 | 1992 | 49.138392682987 | 1991 | 49.171188663252 | 1990 | 49.159705776954 | 1989 | 49.167021352729 | 1988 | 49.256676854084 | 1987 | 49.368980275255 | 1986 | 49.496818232564 | 1985 | 49.620428161913 | 1984 | 49.737525190118 | 1983 | 49.852062252204 | 1982 | 49.972650176374 | 1981 | 50.100896664268 | 1980 | 50.168043190675 | 1979 | 50.166343095167 | 1978 | 50.157662685568 | 1977 | 50.142019816277 | 1976 | 50.124699169319 | 1975 | 50.116157538352 | 1974 | 50.120090813938 | 1973 | 50.128898601489 | 1972 | 50.133470063061 | 1971 | 50.108710385773 | 1970 | 50.025958945788 | 1969 | 49.952820631567 | 1968 | 49.930495116527 | 1967 | 49.911818808195 | 1966 | 49.88336207979 | 1965 | 49.848462882036 | 1964 | 49.819504989732 | 1963 | 49.681466235421 | 1962 | 49.406595146669 | 1961 | 49.109935449524 | 1960 | 48.803493449782 |
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