Year | Value | 2021 | 1.692 | 2020 | 1.712 | 2019 | 1.736 | 2018 | 1.784 | 2017 | 1.845 | 2016 | 1.913 | 2015 | 1.99 | 2014 | 2.059 | 2013 | 2.123 | 2012 | 2.202 | 2011 | 2.261 | 2010 | 2.318 | 2009 | 2.366 | 2008 | 2.359 | 2007 | 2.295 | 2006 | 2.231 | 2005 | 2.235 | 2004 | 2.284 | 2003 | 2.344 | 2002 | 2.413 | 2001 | 2.519 | 2000 | 2.71 | 1999 | 2.961 | 1998 | 3.254 | 1997 | 3.572 | 1996 | 3.931 | 1995 | 4.32 | 1994 | 4.674 | 1993 | 5.045 | 1992 | 5.396 | 1991 | 5.744 | 1990 | 6.089 | 1989 | 6.376 | 1988 | 6.61 | 1987 | 6.79 | 1986 | 6.912 | 1985 | 7.02 | 1984 | 7.096 | 1983 | 7.153 | 1982 | 7.155 | 1981 | 7.159 | 1980 | 7.174 | 1979 | 7.168 | 1978 | 7.137 | 1977 | 7.145 | 1976 | 7.168 | 1975 | 7.187 | 1974 | 7.269 | 1973 | 7.293 | 1972 | 7.247 | 1971 | 7.276 | 1970 | 7.299 | 1969 | 7.264 | 1968 | 7.223 | 1967 | 7.18 | 1966 | 7.095 | 1965 | 7.016 | 1964 | 6.984 | 1963 | 6.943 | 1962 | 6.906 | 1961 | 6.841 | 1960 | 6.804 |
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