Year | Value | 2021 | 16.83852482878 | 2020 | 16.83852482878 | 2019 | 16.838363719933 | 2018 | 16.976099279914 | 2017 | 16.946150900038 | 2016 | 16.771347161371 | 2015 | 16.740674802474 | 2014 | 16.561523856189 | 2013 | 16.494150793165 | 2012 | 16.460231187323 | 2011 | 16.510278742978 | 2010 | 16.549306554817 | 2009 | 16.522271544467 | 2008 | 16.368951952366 | 2007 | 16.184661525278 | 2006 | 15.817099484292 | 2005 | 15.395800171422 | 2004 | 15.169416301919 | 2003 | 15.073293141965 | 2002 | 15.090124552437 | 2001 | 15.285980965205 | 2000 | 15.162040579001 | 1999 | 14.826942497781 | 1998 | 14.621905315666 | 1997 | 14.62649570034 | 1996 | 14.602013648744 | 1995 | 14.597423264069 | 1994 | 14.588242494721 | 1993 | 14.657098264835 | 1992 | 14.588242494721 | 1991 | 14.618845059216 | 1990 | 14.638736726138 | 1989 | 14.59436300762 | 1988 | 14.615784802767 | 1987 | 14.649447623711 | 1986 | 14.683110444655 | 1985 | 14.678520059981 | 1984 | 14.675459803531 | 1983 | 14.709122624476 | 1982 | 14.719833522049 | 1981 | 14.696881598678 | 1980 | 14.647917495486 | 1979 | 14.638736726138 | 1978 | 14.624965572115 | 1977 | 14.612724546317 | 1976 | 14.563760443125 | 1975 | 14.543868776203 | 1974 | 14.527037365731 | 1973 | 14.513266211708 | 1972 | 15.25537840071 | 1971 | 15.25537840071 | 1970 | 15.25537840071 | 1969 | 15.224775836215 | 1968 | 15.209474553968 | 1967 | 15.209474553968 | 1966 | 15.209474553968 | 1965 | 15.19417327172 | 1964 | 15.19417327172 | 1963 | 15.178871989473 | 1962 | 15.163570707225 | 1961 | 15.148269424978 |
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