Year | Value | 2022 | 38.85785126884 | 2021 | 38.333138428982 | 2020 | 37.822404854819 | 2019 | 37.314654050041 | 2018 | 36.810019181072 | 2017 | 36.313015751597 | 2016 | 35.823116672164 | 2015 | 35.340384962239 | 2014 | 34.869961340646 | 2013 | 34.438101091529 | 2012 | 34.015052392865 | 2011 | 33.586385812382 | 2010 | 33.135309907931 | 2009 | 32.656748277676 | 2008 | 32.190827256656 | 2007 | 31.721445702734 | 2006 | 31.298445386545 | 2005 | 30.861603485002 | 2004 | 30.436333358769 | 2003 | 30.023494326785 | 2002 | 29.617313668988 | 2001 | 29.209991432461 | 2000 | 28.809480623055 | 1999 | 28.473450019509 | 1998 | 28.14914956406 | 1997 | 27.817058272799 | 1996 | 27.489373790075 | 1995 | 27.17405463363 | 1994 | 26.834337301733 | 1993 | 26.488236230666 | 1992 | 26.149261027706 | 1991 | 25.805027378331 | 1990 | 25.440785656774 | 1989 | 25.010498331892 | 1988 | 24.581523752977 | 1987 | 24.143477111154 | 1986 | 23.705152886381 | 1985 | 23.269478495647 | 1984 | 22.842487614337 | 1983 | 22.439178639671 | 1982 | 22.065463891378 | 1981 | 21.709574007608 | 1980 | 21.234839373555 | 1979 | 20.739882005291 | 1978 | 20.28247345339 | 1977 | 19.801594370319 | 1976 | 19.331637039275 | 1975 | 18.8623723682 | 1974 | 18.72245815244 | 1973 | 18.293718933331 | 1972 | 17.869655157932 | 1971 | 17.4403921294 | 1970 | 17.017557623663 | 1969 | 16.64276933905 | 1968 | 16.270923320825 | 1967 | 15.910769860413 | 1966 | 15.560290993315 | 1965 | 15.232443143325 | 1964 | 14.906714229936 | 1963 | 14.589605804234 | 1962 | 14.283648261503 | 1961 | 13.993534428009 | 1960 | 13.69985260854 |
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