Year | Value | 2022 | 49.489769841898 | 2021 | 49.504378088675 | 2020 | 49.521503488106 | 2019 | 49.528923139482 | 2018 | 49.528568722368 | 2017 | 49.529918558866 | 2016 | 49.532171252306 | 2015 | 49.535272778315 | 2014 | 49.539396731777 | 2013 | 49.544838627729 | 2012 | 49.551688073998 | 2011 | 49.559741753993 | 2010 | 49.569249956732 | 2009 | 49.580280700234 | 2008 | 49.592555530256 | 2007 | 49.605515410168 | 2006 | 49.619151105327 | 2005 | 49.633041326863 | 2004 | 49.646899622764 | 2003 | 49.660872786008 | 2002 | 49.674210991569 | 2001 | 49.687206318759 | 2000 | 49.700900502339 | 1999 | 49.715601791564 | 1998 | 49.731134531804 | 1997 | 49.747615420314 | 1996 | 49.764966033197 | 1995 | 49.783085932864 | 1994 | 49.801776556746 | 1993 | 49.829249131498 | 1992 | 49.866706764279 | 1991 | 49.906313879641 | 1990 | 49.942904506218 | 1989 | 49.975213636731 | 1988 | 50.007575483619 | 1987 | 50.041275562441 | 1986 | 50.077863966024 | 1985 | 50.115775161573 | 1984 | 50.155804445955 | 1983 | 50.204458224974 | 1982 | 50.314491482778 | 1981 | 50.439648192129 | 1980 | 50.516266498296 | 1979 | 50.580823825846 | 1978 | 50.637531453186 | 1977 | 50.686425925209 | 1976 | 50.720936077012 | 1975 | 50.750935141688 | 1974 | 50.784435882072 | 1973 | 50.810613762173 | 1972 | 50.834391572615 | 1971 | 50.86297656895 | 1970 | 50.89543622763 | 1969 | 50.931805962518 | 1968 | 50.967897201654 | 1967 | 51.000604266901 | 1966 | 51.030876948934 | 1965 | 51.058571247608 | 1964 | 51.08206621767 | 1963 | 51.101968936367 | 1962 | 51.119153159844 | 1961 | 51.133515165861 | 1960 | 51.146021620398 |
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