Year | Value | 2021 | 10.307 | 2020 | 10.62 | 2019 | 9.75 | 2018 | 10.049 | 2017 | 10.62 | 2016 | 10.993 | 2015 | 11.478 | 2014 | 11.989 | 2013 | 12.438 | 2012 | 12.911 | 2011 | 13.292 | 2010 | 13.665 | 2009 | 13.9 | 2008 | 14.08 | 2007 | 14.24 | 2006 | 14.484 | 2005 | 15.206 | 2004 | 16.094 | 2003 | 16.43 | 2002 | 16.401 | 2001 | 16.525 | 2000 | 16.66 | 1999 | 16.765 | 1998 | 17.335 | 1997 | 18.33 | 1996 | 19.493 | 1995 | 19.508 | 1994 | 22.202 | 1993 | 22.429 | 1992 | 23.839 | 1991 | 24.574 | 1990 | 25.923 | 1989 | 26.618 | 1988 | 27.396 | 1987 | 28.411 | 1986 | 29.651 | 1985 | 29.488 | 1984 | 29.814 | 1983 | 30.034 | 1982 | 30.156 | 1981 | 30.165 | 1980 | 30.66 | 1979 | 30.542 | 1978 | 30.125 | 1977 | 29.48 | 1976 | 28.677 | 1975 | 29.163 | 1974 | 29.792 | 1973 | 30.489 | 1972 | 31.236 | 1971 | 32.132 | 1970 | 33.432 | 1969 | 35.29 | 1968 | 37.706 | 1967 | 38.278 | 1966 | 38.814 | 1965 | 39.36 | 1964 | 40.003 | 1963 | 40.601 | 1962 | 41.062 | 1961 | 41.392 | 1960 | 41.814 |
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