Year | Value | 2022 | 49.696142127257 | 2021 | 49.692045700313 | 2020 | 49.689061687382 | 2019 | 49.679792841559 | 2018 | 49.657361604702 | 2017 | 49.632517040107 | 2016 | 49.61927290856 | 2015 | 49.616112962324 | 2014 | 49.61463208405 | 2013 | 49.605048709789 | 2012 | 49.585562937815 | 2011 | 49.566829240267 | 2010 | 49.559428834771 | 2009 | 49.559219307472 | 2008 | 49.559545676615 | 2007 | 49.562660542231 | 2006 | 49.565710446314 | 2005 | 49.5619556495 | 2004 | 49.555231647559 | 2003 | 49.551352094992 | 2002 | 49.547406938639 | 2001 | 49.534559226221 | 2000 | 49.513434224003 | 1999 | 49.497496330401 | 1998 | 49.496125568804 | 1997 | 49.496254561829 | 1996 | 49.489115119835 | 1995 | 49.492733264155 | 1994 | 49.507841103414 | 1993 | 49.524448128283 | 1992 | 49.551424755238 | 1991 | 49.572956451192 | 1990 | 49.574483378725 | 1989 | 49.58521026298 | 1988 | 49.609872271795 | 1987 | 49.626864189656 | 1986 | 49.633656609373 | 1985 | 49.646168255732 | 1984 | 49.670442727787 | 1983 | 49.700253060579 | 1982 | 49.732243285048 | 1981 | 49.763541642405 | 1980 | 49.794631175313 | 1979 | 49.828874900678 | 1978 | 49.87509332216 | 1977 | 49.931474640768 | 1976 | 49.987130000306 | 1975 | 50.037797824816 | 1974 | 50.078636946731 | 1973 | 50.11379640476 | 1972 | 50.154887758519 | 1971 | 50.168189683809 | 1970 | 50.134280699824 | 1969 | 50.130636485604 | 1968 | 50.167497679545 | 1967 | 50.195829586854 | 1966 | 50.225507239208 | 1965 | 50.268043184947 | 1964 | 50.321204350998 | 1963 | 50.381389915822 | 1962 | 50.448812971728 | 1961 | 50.518258934542 | 1960 | 50.579066047936 |
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