Year | Value | 2022 | 6.39 | 2021 | 6.408 | 2020 | 6.419 | 2019 | 6.424 | 2018 | 6.422 | 2017 | 6.413 | 2016 | 6.398 | 2015 | 6.376 | 2014 | 6.349 | 2013 | 6.314 | 2012 | 6.274 | 2011 | 6.227 | 2010 | 6.175 | 2009 | 6.116 | 2008 | 6.058 | 2007 | 6.001 | 2006 | 5.944 | 2005 | 5.888 | 2004 | 5.832 | 2003 | 5.776 | 2002 | 5.722 | 2001 | 5.667 | 2000 | 5.613 | 1999 | 5.702 | 1998 | 5.839 | 1997 | 5.98 | 1996 | 6.124 | 1995 | 6.271 | 1994 | 6.422 | 1993 | 6.576 | 1992 | 6.733 | 1991 | 6.894 | 1990 | 7.058 | 1989 | 8.085 | 1988 | 9.587 | 1987 | 11.34 | 1986 | 13.363 | 1985 | 15.683 | 1984 | 18.316 | 1983 | 21.289 | 1982 | 24.594 | 1981 | 28.228 | 1980 | 32.165 | 1979 | 33.822 | 1978 | 34.66 | 1977 | 35.508 | 1976 | 36.363 | 1975 | 37.23 | 1974 | 38.104 | 1973 | 38.986 | 1972 | 39.873 | 1971 | 40.77 | 1970 | 41.672 | 1969 | 42.923 | 1968 | 44.298 | 1967 | 45.686 | 1966 | 47.079 | 1965 | 48.476 | 1964 | 49.874 | 1963 | 51.276 | 1962 | 52.673 | 1961 | 54.067 | 1960 | 55.453 |
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