Year | Value | 2022 | 57.17 | 2021 | 56.776 | 2020 | 56.397 | 2019 | 56.031 | 2018 | 55.68 | 2017 | 55.343 | 2016 | 55.021 | 2015 | 54.714 | 2014 | 54.422 | 2013 | 54.145 | 2012 | 53.883 | 2011 | 53.637 | 2010 | 53.406 | 2009 | 53.19 | 2008 | 52.99 | 2007 | 52.79 | 2006 | 52.589 | 2005 | 52.389 | 2004 | 52.189 | 2003 | 51.988 | 2002 | 51.787 | 2001 | 51.587 | 2000 | 51.386 | 1999 | 51.185 | 1998 | 51.278 | 1997 | 51.588 | 1996 | 51.896 | 1995 | 52.206 | 1994 | 52.515 | 1993 | 52.824 | 1992 | 53.132 | 1991 | 53.441 | 1990 | 53.749 | 1989 | 54.057 | 1988 | 54.094 | 1987 | 53.895 | 1986 | 53.697 | 1985 | 53.498 | 1984 | 53.299 | 1983 | 53.139 | 1982 | 53.018 | 1981 | 52.897 | 1980 | 52.777 | 1979 | 52.655 | 1978 | 52.492 | 1977 | 52.294 | 1976 | 52.096 | 1975 | 51.897 | 1974 | 51.698 | 1973 | 51.371 | 1972 | 50.917 | 1971 | 50.462 | 1970 | 50.008 | 1969 | 49.963 | 1968 | 50.263 | 1967 | 50.564 | 1966 | 50.864 | 1965 | 51.164 | 1964 | 51.464 | 1963 | 51.764 | 1962 | 52.064 | 1961 | 52.364 | 1960 | 52.663 |
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