Year | Value | 2021 | 1.6 | 2020 | 1.31 | 2019 | 1.34 | 2018 | 1.42 | 2017 | 1.43 | 2016 | 1.5 | 2015 | 1.49 | 2014 | 1.5 | 2013 | 1.5 | 2012 | 1.5 | 2011 | 1.46 | 2010 | 1.6 | 2009 | 1.5 | 2008 | 1.47 | 2007 | 1.46 | 2006 | 1.46 | 2005 | 1.5 | 2004 | 1.529 | 2003 | 1.744 | 2002 | 1.789 | 2001 | 1.735 | 2000 | 1.861 | 1999 | 1.775 | 1998 | 1.894 | 1997 | 1.916 | 1996 | 2.061 | 1995 | 2.131 | 1994 | 2.224 | 1993 | 2.098 | 1992 | 2.12 | 1991 | 2.189 | 1990 | 2.185 | 1989 | 2.202 | 1988 | 2.234 | 1987 | 2.272 | 1986 | 2.286 | 1985 | 2.318 | 1984 | 2.356 | 1983 | 2.402 | 1982 | 2.438 | 1981 | 2.423 | 1980 | 2.417 | 1979 | 2.429 | 1978 | 2.448 | 1977 | 2.487 | 1976 | 2.543 | 1975 | 2.592 | 1974 | 2.636 | 1973 | 2.69 | 1972 | 2.772 | 1971 | 2.863 | 1970 | 2.965 | 1969 | 3.101 | 1968 | 3.219 | 1967 | 3.332 | 1966 | 3.432 | 1965 | 3.516 | 1964 | 3.56 | 1963 | 3.611 | 1962 | 3.682 | 1961 | 3.809 | 1960 | 3.967 |
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