Year | Value | 2022 | 51.715805274809 | 2021 | 51.743370163885 | 2020 | 51.769087101703 | 2019 | 51.792497625831 | 2018 | 51.81475289794 | 2017 | 51.836263235691 | 2016 | 51.857537899595 | 2015 | 51.878691239735 | 2014 | 51.900128643293 | 2013 | 51.922992844339 | 2012 | 51.946713752416 | 2011 | 51.972324199389 | 2010 | 52.015008092351 | 2009 | 52.074371462757 | 2008 | 52.134863015123 | 2007 | 52.196711269763 | 2006 | 52.259876397502 | 2005 | 52.325362609315 | 2004 | 52.393185393149 | 2003 | 52.467341722098 | 2002 | 52.542860678691 | 2001 | 52.613368236938 | 2000 | 52.681432413169 | 1999 | 52.753902368176 | 1998 | 52.829281091481 | 1997 | 52.903915840557 | 1996 | 52.984689545259 | 1995 | 53.07141161563 | 1994 | 53.160463801874 | 1993 | 53.253276106114 | 1992 | 53.350924243735 | 1991 | 53.442896316609 | 1990 | 53.522723801961 | 1989 | 53.59918998034 | 1988 | 53.679866845183 | 1987 | 53.764639563842 | 1986 | 53.853751930901 | 1985 | 53.946758269216 | 1984 | 54.042257851147 | 1983 | 54.140023033591 | 1982 | 54.239146687933 | 1981 | 54.293942781776 | 1980 | 54.285045311594 | 1979 | 54.267907293722 | 1978 | 54.25937698665 | 1977 | 54.246013133208 | 1976 | 54.221392914264 | 1975 | 54.195661841619 | 1974 | 54.175253055458 | 1973 | 54.155569717908 | 1972 | 54.134523164172 | 1971 | 54.103385112428 | 1970 | 54.05083131473 | 1969 | 53.985563853389 | 1968 | 53.91157016715 | 1967 | 53.829020301289 | 1966 | 53.733225574394 | 1965 | 53.624426573556 | 1964 | 53.50812407681 | 1963 | 53.385837988543 | 1962 | 53.254046911133 | 1961 | 53.10235481962 | 1960 | 52.957373514869 |
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