Year | Value | 2021 | 57.474 | 2020 | 57.787 | 2019 | 58.173 | 2018 | 58.29 | 2017 | 57.797 | 2016 | 57.623 | 2015 | 57.184 | 2014 | 56.727 | 2013 | 56.277 | 2012 | 56.033 | 2011 | 55.527 | 2010 | 54.959 | 2009 | 54.493 | 2008 | 53.745 | 2007 | 52.878 | 2006 | 52.234 | 2005 | 51.479 | 2004 | 50.953 | 2003 | 50.32 | 2002 | 49.752 | 2001 | 49.471 | 2000 | 49.225 | 1999 | 48.875 | 1998 | 48.691 | 1997 | 48.176 | 1996 | 48.313 | 1995 | 48.224 | 1994 | 48.071 | 1993 | 48.12 | 1992 | 48.382 | 1991 | 48.396 | 1990 | 48.383 | 1989 | 48.225 | 1988 | 48.178 | 1987 | 48.03 | 1986 | 47.981 | 1985 | 47.814 | 1984 | 47.493 | 1983 | 46.892 | 1982 | 46.376 | 1981 | 45.626 | 1980 | 45.236 | 1979 | 44.506 | 1978 | 43.723 | 1977 | 42.787 | 1976 | 41.92 | 1975 | 40.962 | 1974 | 40.009 | 1973 | 39.205 | 1972 | 38.763 | 1971 | 38.194 | 1970 | 37.925 | 1969 | 37.577 | 1968 | 37.293 | 1967 | 37.111 | 1966 | 36.757 | 1965 | 36.531 | 1964 | 36.124 | 1963 | 35.941 | 1962 | 35.598 | 1961 | 35.145 | 1960 | 34.837 |
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