Year | Value | 2022 | 53.926676472336 | 2021 | 53.878644001036 | 2020 | 53.843402402733 | 2019 | 53.817774043699 | 2018 | 53.801288635852 | 2017 | 53.786929980343 | 2016 | 53.779602731442 | 2015 | 53.702770249835 | 2014 | 53.552679523891 | 2013 | 53.404733317646 | 2012 | 53.26546918328 | 2011 | 53.115340211312 | 2010 | 52.927736630869 | 2009 | 52.724348606228 | 2008 | 52.526076573923 | 2007 | 52.329729701936 | 2006 | 52.122239549923 | 2005 | 51.891932879277 | 2004 | 51.648930494196 | 2003 | 51.405330781852 | 2002 | 51.16375062839 | 2001 | 50.928627655317 | 2000 | 50.71570501226 | 1999 | 50.518724503968 | 1998 | 50.319299083402 | 1997 | 50.115769706311 | 1996 | 49.916854084444 | 1995 | 49.763119250451 | 1994 | 49.64111603939 | 1993 | 49.513547881969 | 1992 | 49.380585034002 | 1991 | 49.240670170595 | 1990 | 49.100619432074 | 1989 | 48.956265466629 | 1988 | 48.803934328776 | 1987 | 48.645925371419 | 1986 | 48.487226257107 | 1985 | 48.337263104988 | 1984 | 48.192871155179 | 1983 | 48.034082191843 | 1982 | 47.857876233451 | 1981 | 47.703546182535 | 1980 | 47.709209760926 | 1979 | 47.848690021573 | 1978 | 47.986410831409 | 1977 | 48.126081078213 | 1976 | 48.271711012788 | 1975 | 48.422185378391 | 1974 | 48.572052925631 | 1973 | 48.720515996915 | 1972 | 48.871299868494 | 1971 | 49.006517144272 | 1970 | 49.039587648468 | 1969 | 48.987517144912 | 1968 | 48.936957671054 | 1967 | 48.885126882653 | 1966 | 48.828645209266 | 1965 | 48.766209267055 | 1964 | 48.696996070574 | 1963 | 48.624192657708 | 1962 | 48.551297615145 | 1961 | 48.485777709841 | 1960 | 48.457156470138 |
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