Year | Value | 2021 | 1.806 | 2020 | 1.77 | 2019 | 1.78 | 2018 | 1.809 | 2017 | 1.81 | 2016 | 1.89 | 2015 | 1.868 | 2014 | 1.822 | 2013 | 1.654 | 2012 | 1.659 | 2011 | 1.66 | 2010 | 1.698 | 2009 | 1.704 | 2008 | 1.638 | 2007 | 1.574 | 2006 | 1.541 | 2005 | 1.531 | 2004 | 1.539 | 2003 | 1.48 | 2002 | 1.437 | 2001 | 1.463 | 2000 | 1.499 | 1999 | 1.56 | 1998 | 1.651 | 1997 | 1.759 | 1996 | 1.725 | 1995 | 1.831 | 1994 | 1.989 | 1993 | 2.105 | 1992 | 2.218 | 1991 | 2.281 | 1990 | 2.388 | 1989 | 2.467 | 1988 | 2.631 | 1987 | 2.775 | 1986 | 2.741 | 1985 | 2.66 | 1984 | 2.668 | 1983 | 2.579 | 1982 | 2.453 | 1981 | 2.402 | 1980 | 2.377 | 1979 | 2.386 | 1978 | 2.394 | 1977 | 2.436 | 1976 | 2.477 | 1975 | 2.526 | 1974 | 2.563 | 1973 | 2.568 | 1972 | 2.562 | 1971 | 2.559 | 1970 | 2.56 | 1969 | 2.566 | 1968 | 2.597 | 1967 | 2.629 | 1966 | 2.657 | 1965 | 2.685 | 1964 | 2.709 | 1963 | 2.89 | 1962 | 3.043 | 1961 | 3.229 | 1960 | 3.328 |
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