Year | Value | 2021 | 52.525 | 2020 | 52.777 | 2019 | 53.259 | 2018 | 52.825 | 2017 | 52.308 | 2016 | 52.083 | 2015 | 51.589 | 2014 | 51.202 | 2013 | 50.781 | 2012 | 50.54 | 2011 | 50.009 | 2010 | 49.584 | 2009 | 49.196 | 2008 | 49.024 | 2007 | 48.751 | 2006 | 48.286 | 2005 | 48.312 | 2004 | 48.232 | 2003 | 48.206 | 2002 | 47.946 | 2001 | 47.85 | 2000 | 47.443 | 1999 | 47.372 | 1998 | 47.224 | 1997 | 47.217 | 1996 | 47.013 | 1995 | 46.711 | 1994 | 46.449 | 1993 | 46.318 | 1992 | 46.102 | 1991 | 45.941 | 1990 | 44.686 | 1989 | 45.875 | 1988 | 45.785 | 1987 | 42.798 | 1986 | 45.21 | 1985 | 45.05 | 1984 | 44.515 | 1983 | 44.179 | 1982 | 43.73 | 1981 | 43.312 | 1980 | 43.06 | 1979 | 42.81 | 1978 | 42.504 | 1977 | 42.255 | 1976 | 42.036 | 1975 | 41.872 | 1974 | 41.785 | 1973 | 41.78 | 1972 | 41.399 | 1971 | 40.19 | 1970 | 40.603 | 1969 | 40.265 | 1968 | 39.903 | 1967 | 39.479 | 1966 | 39.15 | 1965 | 39.12 | 1964 | 39.333 | 1963 | 39.072 | 1962 | 38.835 | 1961 | 38.631 | 1960 | 38.374 |
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