Year | Value | 2022 | 49.508722251876 | 2021 | 49.488404607523 | 2020 | 49.470943797673 | 2019 | 49.455485231615 | 2018 | 49.437208777962 | 2017 | 49.419284087738 | 2016 | 49.414608245066 | 2015 | 49.423184245284 | 2014 | 49.432134712425 | 2013 | 49.442102869297 | 2012 | 49.455577062253 | 2011 | 49.467664999713 | 2010 | 49.48370807578 | 2009 | 49.50585728325 | 2008 | 49.525460492427 | 2007 | 49.550981938557 | 2006 | 49.579549442077 | 2005 | 49.604650588331 | 2004 | 49.635084747943 | 2003 | 49.669165069929 | 2002 | 49.704417889001 | 2001 | 49.740205413967 | 2000 | 49.775111085913 | 1999 | 49.811100093356 | 1998 | 49.843320212066 | 1997 | 49.873788698395 | 1996 | 49.907190764731 | 1995 | 49.939027628627 | 1994 | 49.96323975425 | 1993 | 49.987424805909 | 1992 | 50.001845334741 | 1991 | 49.99650540564 | 1990 | 49.990752511782 | 1989 | 49.981495653399 | 1988 | 49.964655326837 | 1987 | 49.915439265359 | 1986 | 49.837793998378 | 1985 | 49.710513125628 | 1984 | 49.538808589018 | 1983 | 49.403368293401 | 1982 | 49.304376589529 | 1981 | 49.216172375292 | 1980 | 49.147412140232 | 1979 | 49.078745567756 | 1978 | 49.021606382385 | 1977 | 48.985824487021 | 1976 | 48.958030439104 | 1975 | 48.927195369136 | 1974 | 48.893531265146 | 1973 | 48.856630559627 | 1972 | 48.816351345688 | 1971 | 48.772846270608 | 1970 | 48.72670074159 | 1969 | 48.67799661327 | 1968 | 48.626004851782 | 1967 | 48.570463824784 | 1966 | 48.511803001631 | 1965 | 48.450285186417 | 1964 | 48.385273112733 | 1963 | 48.315893099236 | 1962 | 48.242371792678 | 1961 | 48.16500078497 | 1960 | 48.083054198184 |
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