Year | Value | 2021 | 57.392 | 2020 | 57.612 | 2019 | 58.763 | 2018 | 58.263 | 2017 | 57.969 | 2016 | 57.447 | 2015 | 56.925 | 2014 | 56.422 | 2013 | 56.023 | 2012 | 55.478 | 2011 | 54.767 | 2010 | 53.923 | 2009 | 53.344 | 2008 | 52.496 | 2007 | 52.098 | 2006 | 51.171 | 2005 | 50.068 | 2004 | 49.902 | 2003 | 49.143 | 2002 | 48.599 | 2001 | 48.053 | 2000 | 47.684 | 1999 | 44.861 | 1998 | 44.222 | 1997 | 45.994 | 1996 | 47.088 | 1995 | 46.991 | 1994 | 46.248 | 1993 | 46.366 | 1992 | 46.016 | 1991 | 45.571 | 1990 | 45.239 | 1989 | 44.896 | 1988 | 44.54 | 1987 | 43.997 | 1986 | 43.593 | 1985 | 43.28 | 1984 | 42.971 | 1983 | 42.785 | 1982 | 42.503 | 1981 | 42.142 | 1980 | 41.873 | 1979 | 41.495 | 1978 | 41.096 | 1977 | 40.735 | 1976 | 40.47 | 1975 | 40.064 | 1974 | 39.746 | 1973 | 35.219 | 1972 | 34.931 | 1971 | 34.584 | 1970 | 34.254 | 1969 | 33.996 | 1968 | 33.615 | 1967 | 33.283 | 1966 | 32.993 | 1965 | 32.714 | 1964 | 32.369 | 1963 | 32.07 | 1962 | 36.121 | 1961 | 35.926 | 1960 | 35.655 |
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