Year | Value | 2021 | 9.5220772711538 | 2020 | 10.222821087285 | 2019 | 11.502659539726 | 2018 | 11.930998970374 | 2017 | 13.114698187781 | 2016 | 13.825411569526 | 2015 | 13.015797808999 | 2014 | 14.19630074875 | 2013 | 13.714473170368 | 2012 | 14.719983340395 | 2011 | 13.917925885053 | 2010 | 13.100289676966 | 2009 | 13.159556674609 | 2008 | 13.291545938005 | 2007 | 13.222345384464 | 2006 | 13.184659487362 | 2005 | 13.429663784628 | 2004 | 13.432066258144 | 2003 | 13.51753009771 | 2002 | 13.854717605803 | 2001 | 14.2315939348 | 2000 | 14.722366046435 | 1999 | 15.178073062353 | 1998 | 15.998427919633 | 1997 | 16.725333875867 | 1996 | 17.155004465261 | 1995 | 17.453361978186 | 1994 | 18.034982315013 | 1993 | 18.446343129299 | 1992 | 18.83385219152 | 1991 | 19.997439735666 | 1990 | 21.084836964186 | 1989 | 21.672569141072 | 1988 | 22.45042525267 | 1987 | 23.327001361918 | 1986 | 22.954855351633 | 1985 | 22.206980392788 | 1984 | 21.686307930475 | 1983 | 22.02741852751 | 1982 | 23.354177196586 | 1981 | 22.572972453823 | 1980 | 20.975335561363 | 1979 | 20.769374502338 | 1978 | 21.119137224737 | 1977 | 21.588654680388 | 1976 | 22.264656375469 | 1975 | 24.251078263731 | 1974 | 25.450987707732 | 1973 | 27.464882956738 | 1972 | 28.708473405607 | 1971 | 29.273219249479 | 1970 | 31.023376513979 | 1969 | 31.52743966025 | 1968 | 32.593726076244 | 1967 | 31.795213877333 | 1966 | 32.479717795941 | 1965 | 34.46546782233 | 1964 | 35.578090456625 | 1963 | 38.517304638664 | 1962 | 34.972602656379 | 1961 | 23.709253657902 | 1960 | 25.79419229901 |
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