Year | Value | 2021 | 57.414 | 2020 | 58.051 | 2019 | 59.092 | 2018 | 58.545 | 2017 | 57.809 | 2016 | 57.293 | 2015 | 56.93 | 2014 | 56.362 | 2013 | 55.775 | 2012 | 55.139 | 2011 | 53.038 | 2010 | 52.538 | 2009 | 53.446 | 2008 | 52.835 | 2007 | 52.196 | 2006 | 52.212 | 2005 | 52.173 | 2004 | 52.071 | 2003 | 52.106 | 2002 | 52.147 | 2001 | 52.16 | 2000 | 52.066 | 1999 | 51.976 | 1998 | 52.09 | 1997 | 51.623 | 1996 | 51.97 | 1995 | 52.131 | 1994 | 51.784 | 1993 | 52.117 | 1992 | 28.569 | 1991 | 28.415 | 1990 | 51.088 | 1989 | 50.693 | 1988 | 48.542 | 1987 | 50.32 | 1986 | 49.765 | 1985 | 49.679 | 1984 | 49.881 | 1983 | 49.591 | 1982 | 49.257 | 1981 | 49.089 | 1980 | 48.914 | 1979 | 48.731 | 1978 | 48.527 | 1977 | 48.348 | 1976 | 45.963 | 1975 | 45.574 | 1974 | 45.206 | 1973 | 47.563 | 1972 | 47.372 | 1971 | 47.178 | 1970 | 46.987 | 1969 | 46.799 | 1968 | 46.601 | 1967 | 46.397 | 1966 | 46.186 | 1965 | 45.969 | 1964 | 45.724 | 1963 | 45.523 | 1962 | 45.298 | 1961 | 44.972 | 1960 | 44.858 |
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