Year | Value | 2021 | 5.376 | 2020 | 3.859 | 2019 | 3.391 | 2018 | 3.31 | 2017 | 3.219 | 2016 | 3.126 | 2015 | 3.037 | 2014 | 2.952 | 2013 | 2.887 | 2012 | 2.848 | 2011 | 2.832 | 2010 | 2.84 | 2009 | 2.842 | 2008 | 2.839 | 2007 | 2.849 | 2006 | 2.791 | 2005 | 2.696 | 2004 | 2.588 | 2003 | 2.482 | 2002 | 2.393 | 2001 | 2.322 | 2000 | 2.284 | 1999 | 2.292 | 1998 | 2.412 | 1997 | 2.509 | 1996 | 2.662 | 1995 | 2.822 | 1994 | 2.975 | 1993 | 3.089 | 1992 | 3.17 | 1991 | 3.231 | 1990 | 3.275 | 1989 | 3.32 | 1988 | 3.407 | 1987 | 3.537 | 1986 | 3.638 | 1985 | 3.877 | 1984 | 4.11 | 1983 | 4.348 | 1982 | 4.636 | 1981 | 4.934 | 1980 | 5.214 | 1979 | 5.519 | 1978 | 5.784 | 1977 | 6.085 | 1976 | 6.332 | 1975 | 6.573 | 1974 | 6.788 | 1973 | 6.973 | 1972 | 7.154 | 1971 | 7.395 | 1970 | 7.624 | 1969 | 7.843 | 1968 | 8.055 | 1967 | 8.274 | 1966 | 8.504 | 1965 | 8.73 | 1964 | 8.94 | 1963 | 9.104 | 1962 | 9.261 | 1961 | 9.431 | 1960 | 9.628 |
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