Year | Value | 2022 | 49.892421883108 | 2021 | 49.879531096071 | 2020 | 49.863006580296 | 2019 | 49.848939319432 | 2018 | 49.839284967303 | 2017 | 49.830616037607 | 2016 | 49.82130945092 | 2015 | 49.812319933293 | 2014 | 49.805522380644 | 2013 | 49.799584379553 | 2012 | 49.792927997989 | 2011 | 49.785161493698 | 2010 | 49.777979733547 | 2009 | 49.771375508356 | 2008 | 49.764292920967 | 2007 | 49.757145953343 | 2006 | 49.749758384656 | 2005 | 49.741712777646 | 2004 | 49.733372722535 | 2003 | 49.725005457449 | 2002 | 49.717071855206 | 2001 | 49.710568373644 | 2000 | 49.704861906954 | 1999 | 49.700081260584 | 1998 | 49.694045217293 | 1997 | 49.684089210927 | 1996 | 49.671117020252 | 1995 | 49.65500664441 | 1994 | 49.6367988164 | 1993 | 49.617924515788 | 1992 | 49.598225016264 | 1991 | 49.578465185083 | 1990 | 49.55850752323 | 1989 | 49.537619514061 | 1988 | 49.515528095265 | 1987 | 49.492177115885 | 1986 | 49.467437654415 | 1985 | 49.440307609008 | 1984 | 49.41067746731 | 1983 | 49.37908420638 | 1982 | 49.345659284242 | 1981 | 49.309952094707 | 1980 | 49.269935820146 | 1979 | 49.189816047597 | 1978 | 49.070031958134 | 1977 | 48.948454508006 | 1976 | 48.798060452685 | 1975 | 48.750176124722 | 1974 | 48.861788283172 | 1973 | 48.996937433543 | 1972 | 49.135903523808 | 1971 | 49.295154556976 | 1970 | 49.387121743092 | 1969 | 49.381671384618 | 1968 | 49.316323376099 | 1967 | 49.240645917868 | 1966 | 49.191380230216 | 1965 | 49.148459119842 | 1964 | 49.125436692032 | 1963 | 49.103695848015 | 1962 | 49.08000706904 | 1961 | 49.051697111895 | 1960 | 49.041048337791 |
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