Year | Value | 2021 | 10.536841634136 | 2020 | 10.620631271451 | 2019 | 10.891940012401 | 2018 | 10.48452168863 | 2017 | 10.567606128883 | 2016 | 10.722379417852 | 2015 | 11.680071960666 | 2014 | 11.987585911778 | 2013 | 12.428442926821 | 2012 | 12.270116824981 | 2011 | 12.302325581395 | 2010 | 12.529424609673 | 2009 | 13.112566874113 | 2008 | 13.340002186509 | 2007 | 12.553296162676 | 2006 | 13.57537990598 | 2005 | 14.272001749207 | 2004 | 16.204699453552 | 2003 | 16.988196721311 | 2002 | 17.881420765027 | 2001 | 17.798469945355 | 2000 | 19.128633879781 | 1999 | 18.743169398907 | 1998 | 19.655737704918 | 1997 | 20.568306010929 | 1996 | 21.857923497268 | 1995 | 23.530054644809 | 1994 | 24.043715846994 | 1993 | 24.48087431694 | 1992 | 24.863387978142 | 1991 | 25.234972677596 | 1990 | 25.617486338798 | 1989 | 25.989071038251 | 1988 | 26.043715846994 | 1987 | 26.098360655738 | 1986 | 26.153005464481 | 1985 | 26.207650273224 | 1984 | 26.262295081967 | 1983 | 26.31693989071 | 1982 | 26.371584699454 | 1981 | 26.426229508197 | 1980 | 26.48087431694 | 1979 | 26.535519125683 | 1978 | 26.590163934426 | 1977 | 26.644808743169 | 1976 | 26.699453551913 | 1975 | 26.754098360656 | 1974 | 26.808743169399 | 1973 | 26.863387978142 | 1972 | 26.918032786885 | 1971 | 26.96174863388 | 1970 | 27.005464480874 | 1969 | 27.049180327869 | 1968 | 27.092896174863 | 1967 | 27.136612021858 | 1966 | 27.180327868853 | 1965 | 27.224043715847 | 1964 | 27.267759562842 | 1963 | 27.311475409836 | 1962 | 27.355191256831 | 1961 | 27.398907103825 |
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