Year | Value | 2021 | 22.969987080259 | 2020 | 22.970386062607 | 2019 | 22.867488453467 | 2018 | 22.957812563515 | 2017 | 22.960554667614 | 2016 | 22.85136394267 | 2015 | 22.786986559217 | 2014 | 22.772889883774 | 2013 | 22.811616326555 | 2012 | 22.776351732614 | 2011 | 22.749874601911 | 2010 | 22.72674881499 | 2009 | 22.677349099498 | 2008 | 22.697720493302 | 2007 | 22.962924743747 | 2006 | 22.913842226616 | 2005 | 22.859218867318 | 2004 | 24.799467105058 | 2003 | 24.698411788865 | 2002 | 24.610927782932 | 2001 | 24.544768809131 | 2000 | 24.463706724017 | 1999 | 24.543634014119 | 1998 | 24.695488110746 | 1997 | 24.585091196839 | 1996 | 24.69487762525 | 1995 | 24.644610293454 | 1994 | 24.635176736535 | 1993 | 24.578916558884 | 1992 | 24.447587558451 | 1991 | 24.238009518807 | 1990 | 24.017889989981 | 1989 | 24.007547484133 | 1988 | 24.055812511424 | 1987 | 23.958634604127 | 1986 | 23.887231979861 | 1985 | 23.882257396511 | 1984 | 23.842062763046 | 1983 | 23.758927063353 | 1982 | 23.676163878972 | 1981 | 23.583643569946 | 1980 | 24.010578509337 | 1979 | 24.148825651266 | 1978 | 24.016015844626 | 1977 | 24.053614439711 | 1976 | 24.066802869988 | 1975 | 24.032906290418 | 1974 | 24.143388315976 | 1973 | 24.130778325625 | 1972 | 24.074789622373 | 1971 | 23.839481350026 | 1970 | 23.59167883313 | 1969 | 23.504913245982 | 1968 | 23.424626156007 | 1967 | 23.387259109808 | 1966 | 23.311830892714 | 1965 | 23.31275639231 | 1964 | 23.281983530735 | 1963 | 23.273654034368 | 1962 | 23.243112547692 | 1961 | 23.2534087307 |
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