Year | Value | 2021 | 11.788 | 2020 | 11.834 | 2019 | 11.855 | 2018 | 11.94 | 2017 | 12.13 | 2016 | 12.7 | 2015 | 13.211 | 2014 | 13.545 | 2013 | 13.697 | 2012 | 13.857 | 2011 | 14.109 | 2010 | 14.327 | 2009 | 14.464 | 2008 | 14.459 | 2007 | 14.301 | 2006 | 14.139 | 2005 | 14.169 | 2004 | 14.379 | 2003 | 14.802 | 2002 | 15.367 | 2001 | 15.658 | 2000 | 15.963 | 1999 | 16.526 | 1998 | 17.195 | 1997 | 17.847 | 1996 | 18.542 | 1995 | 19.155 | 1994 | 19.918 | 1993 | 20.503 | 1992 | 21.048 | 1991 | 21.866 | 1990 | 22.19 | 1989 | 22.39 | 1988 | 22.473 | 1987 | 22.527 | 1986 | 22.53 | 1985 | 22.521 | 1984 | 22.573 | 1983 | 22.615 | 1982 | 22.755 | 1981 | 23.009 | 1980 | 23.294 | 1979 | 23.645 | 1978 | 24.052 | 1977 | 24.462 | 1976 | 24.931 | 1975 | 25.477 | 1974 | 26.103 | 1973 | 26.797 | 1972 | 27.435 | 1971 | 28.031 | 1970 | 28.76 | 1969 | 29.526 | 1968 | 30.257 | 1967 | 30.916 | 1966 | 31.644 | 1965 | 32.357 | 1964 | 33.063 | 1963 | 33.717 | 1962 | 34.277 | 1961 | 34.825 | 1960 | 35.275 |
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