Year | Value | 2022 | 26.942466293982 | 2021 | 27.185796070975 | 2020 | 27.392897003447 | 2019 | 27.595960022119 | 2018 | 27.798519210685 | 2017 | 27.993985464127 | 2016 | 28.182638105979 | 2015 | 28.366754473566 | 2014 | 28.545367633234 | 2013 | 28.716774828932 | 2012 | 28.889050376524 | 2011 | 29.064634918634 | 2010 | 29.24189741529 | 2009 | 29.437224573103 | 2008 | 29.641303651968 | 2007 | 29.85356603715 | 2006 | 30.070552635224 | 2005 | 30.284967768459 | 2004 | 30.500472497073 | 2003 | 30.713474898005 | 2002 | 30.924076557774 | 2001 | 31.124940106824 | 2000 | 31.280024706814 | 1999 | 31.408947977629 | 1998 | 31.526134057231 | 1997 | 31.634369466242 | 1996 | 31.736777090559 | 1995 | 31.838420330385 | 1994 | 31.951058670144 | 1993 | 32.062549917166 | 1992 | 32.167332391516 | 1991 | 32.27837648171 | 1990 | 32.407775838036 | 1989 | 32.552060502941 | 1988 | 32.753369907971 | 1987 | 33.03064633471 | 1986 | 33.308984701556 | 1985 | 33.566981939026 | 1984 | 33.830601873418 | 1983 | 34.103719600145 | 1982 | 34.387329943749 | 1981 | 34.689627423088 | 1980 | 35.026865122405 | 1979 | 35.336829027836 | 1978 | 35.690602067542 | 1977 | 36.080537658687 | 1976 | 36.46628494555 | 1975 | 36.849640051874 | 1974 | 37.258970191268 | 1973 | 37.701099102314 | 1972 | 38.153131382625 | 1971 | 38.618513071879 | 1970 | 39.094126715708 | 1969 | 39.584231374898 | 1968 | 40.082002075675 | 1967 | 40.607311079441 | 1966 | 41.15076978553 | 1965 | 41.708672785579 | 1964 | 42.269430690124 | 1963 | 42.820376823039 | 1962 | 43.371971435245 | 1961 | 43.898277100917 | 1960 | 44.426854090395 |
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