Year | Value | 2022 | 51.236269017878 | 2021 | 51.260809169375 | 2020 | 51.281285851017 | 2019 | 51.295387223519 | 2018 | 51.327218897606 | 2017 | 51.389924930378 | 2016 | 51.451852875014 | 2015 | 51.503558536591 | 2014 | 51.537210869437 | 2013 | 51.559724693675 | 2012 | 51.589594941165 | 2011 | 51.606838322198 | 2010 | 51.596534411412 | 2009 | 51.579405018642 | 2008 | 51.568402039787 | 2007 | 51.557107242069 | 2006 | 51.548226941263 | 2005 | 51.55047581201 | 2004 | 51.569061749917 | 2003 | 51.595555433658 | 2002 | 51.61431380638 | 2001 | 51.620446729417 | 2000 | 51.617052417761 | 1999 | 51.608713506146 | 1998 | 51.595809868494 | 1997 | 51.582472270921 | 1996 | 51.569999339004 | 1995 | 51.55581970584 | 1994 | 51.540110202517 | 1993 | 51.52589648566 | 1992 | 51.514257031345 | 1991 | 51.501178221711 | 1990 | 51.488112537333 | 1989 | 51.476625808892 | 1988 | 51.4659431488 | 1987 | 51.455702783658 | 1986 | 51.445135365432 | 1985 | 51.43460666198 | 1984 | 51.422705075878 | 1983 | 51.411047607176 | 1982 | 51.399246627818 | 1981 | 51.383392434601 | 1980 | 51.429920836126 | 1979 | 51.474633497387 | 1978 | 51.451954771529 | 1977 | 51.430634796072 | 1976 | 51.41261872279 | 1975 | 51.39787028309 | 1974 | 51.386323345044 | 1973 | 51.377675172273 | 1972 | 51.369945770588 | 1971 | 51.372274482527 | 1970 | 51.386554836172 | 1969 | 51.399585781558 | 1968 | 51.412457057937 | 1967 | 51.429343103039 | 1966 | 51.446825948545 | 1965 | 51.465631041574 | 1964 | 51.486217751927 | 1963 | 51.505192509848 | 1962 | 51.521641425738 | 1961 | 51.522498365378 | 1960 | 51.503590422715 |
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