Year | Value | 2021 | 1.537 | 2020 | 1.537 | 2019 | 1.545 | 2018 | 1.564 | 2017 | 1.598 | 2016 | 1.676 | 2015 | 1.737 | 2014 | 1.774 | 2013 | 1.786 | 2012 | 1.798 | 2011 | 1.823 | 2010 | 1.844 | 2009 | 1.855 | 2008 | 1.85 | 2007 | 1.826 | 2006 | 1.803 | 2005 | 1.803 | 2004 | 1.826 | 2003 | 1.873 | 2002 | 1.935 | 2001 | 1.961 | 2000 | 1.987 | 1999 | 2.044 | 1998 | 2.112 | 1997 | 2.177 | 1996 | 2.245 | 1995 | 2.303 | 1994 | 2.377 | 1993 | 2.43 | 1992 | 2.478 | 1991 | 2.558 | 1990 | 2.579 | 1989 | 2.589 | 1988 | 2.591 | 1987 | 2.59 | 1986 | 2.589 | 1985 | 2.592 | 1984 | 2.601 | 1983 | 2.619 | 1982 | 2.648 | 1981 | 2.689 | 1980 | 2.744 | 1979 | 2.812 | 1978 | 2.892 | 1977 | 2.981 | 1976 | 3.078 | 1975 | 3.182 | 1974 | 3.293 | 1973 | 3.409 | 1972 | 3.53 | 1971 | 3.654 | 1970 | 3.778 | 1969 | 3.902 | 1968 | 4.025 | 1967 | 4.144 | 1966 | 4.259 | 1965 | 4.364 | 1964 | 4.457 | 1963 | 4.536 | 1962 | 4.602 | 1961 | 4.655 | 1960 | 4.697 |
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