Year | Value | 2021 | 3.02 | 2020 | 3.001 | 2019 | 2.858 | 2018 | 2.828 | 2017 | 2.784 | 2016 | 2.738 | 2015 | 2.718 | 2014 | 2.718 | 2013 | 2.793 | 2012 | 2.873 | 2011 | 3.004 | 2010 | 3.112 | 2009 | 3.258 | 2008 | 3.387 | 2007 | 3.622 | 2006 | 3.74 | 2005 | 3.724 | 2004 | 3.984 | 2003 | 3.688 | 2002 | 3.82 | 2001 | 4.087 | 2000 | 4.458 | 1999 | 4.692 | 1998 | 4.878 | 1997 | 5.042 | 1996 | 5.319 | 1995 | 5.854 | 1994 | 6.27 | 1993 | 6.656 | 1992 | 7.064 | 1991 | 7.493 | 1990 | 7.916 | 1989 | 8.338 | 1988 | 8.807 | 1987 | 9.309 | 1986 | 9.771 | 1985 | 10.151 | 1984 | 10.553 | 1983 | 11.078 | 1982 | 11.566 | 1981 | 12.1 | 1980 | 12.628 | 1979 | 13.268 | 1978 | 15.432 | 1977 | 14.598 | 1976 | 15.224 | 1975 | 15.841 | 1974 | 16.642 | 1973 | 17.548 | 1972 | 18.39 | 1971 | 19.206 | 1970 | 20.064 | 1969 | 20.693 | 1968 | 21.213 | 1967 | 22.222 | 1966 | 23.435 | 1965 | 24.259 | 1964 | 24.954 | 1963 | 25.605 | 1962 | 26.166 | 1961 | 26.525 | 1960 | 26.776 |
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