Year | Value | 2022 | 47.869998462363 | 2021 | 47.987272851534 | 2020 | 48.208623908041 | 2019 | 48.447784605915 | 2018 | 48.707245527741 | 2017 | 48.965269855703 | 2016 | 49.226969991768 | 2015 | 49.481031760112 | 2014 | 49.710712053776 | 2013 | 49.9118907491 | 2012 | 50.085716213041 | 2011 | 50.225818103695 | 2010 | 50.328951296104 | 2009 | 50.392779783394 | 2008 | 50.4176332423 | 2007 | 50.418971027541 | 2006 | 50.400659537886 | 2005 | 50.375175520711 | 2004 | 50.355187647689 | 2003 | 50.339993954571 | 2002 | 50.329009955547 | 2001 | 50.325375294355 | 2000 | 50.319379176979 | 1999 | 50.329685870353 | 1998 | 50.355556801186 | 1997 | 50.381777548034 | 1996 | 50.405041672182 | 1995 | 50.431191387171 | 1994 | 50.472444480839 | 1993 | 50.497413662153 | 1992 | 50.509841884479 | 1991 | 50.527843328722 | 1990 | 50.537778604896 | 1989 | 50.54822682885 | 1988 | 50.566763103345 | 1987 | 50.589437704304 | 1986 | 50.619868159084 | 1985 | 50.647345596618 | 1984 | 50.692024525696 | 1983 | 50.782767450406 | 1982 | 50.903529328639 | 1981 | 51.028914166545 | 1980 | 51.135985515023 | 1979 | 51.238081405025 | 1978 | 51.352506825136 | 1977 | 51.47267194007 | 1976 | 51.605229651253 | 1975 | 51.740040485703 | 1974 | 51.862510193351 | 1973 | 51.966994841758 | 1972 | 52.035843271301 | 1971 | 52.084265580024 | 1970 | 52.11214467335 | 1969 | 52.111661299956 | 1968 | 52.093505840185 | 1967 | 52.073240439668 | 1966 | 52.047321376048 | 1965 | 51.997389713879 | 1964 | 51.950678833201 | 1963 | 51.920431128227 | 1962 | 51.895055030228 | 1961 | 51.899027052681 | 1960 | 51.926084329499 |
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