Year | Value | 2021 | 58.915 | 2020 | 59.866 | 2019 | 60.619 | 2018 | 59.923 | 2017 | 60.105 | 2016 | 61.193 | 2015 | 60.76 | 2014 | 60.812 | 2013 | 60.791 | 2012 | 60.317 | 2011 | 59.825 | 2010 | 59.278 | 2009 | 58.82 | 2008 | 58.172 | 2007 | 57.342 | 2006 | 57.133 | 2005 | 57.013 | 2004 | 56.658 | 2003 | 56.032 | 2002 | 55.227 | 2001 | 54.272 | 2000 | 53.762 | 1999 | 53.41 | 1998 | 51.134 | 1997 | 52.153 | 1996 | 51.722 | 1995 | 51.039 | 1994 | 49.531 | 1993 | 50.216 | 1992 | 45.07 | 1991 | 44.353 | 1990 | 43.709 | 1989 | 42.891 | 1988 | 41.572 | 1987 | 36.739 | 1986 | 36.389 | 1985 | 29.896 | 1984 | 29.793 | 1983 | 35.518 | 1982 | 35.212 | 1981 | 38.312 | 1980 | 37.799 | 1979 | 37.314 | 1978 | 39.022 | 1977 | 40.492 | 1976 | 39.892 | 1975 | 39.35 | 1974 | 38.792 | 1973 | 38.241 | 1972 | 37.681 | 1971 | 37.178 | 1970 | 36.692 | 1969 | 36.206 | 1968 | 35.712 | 1967 | 35.225 | 1966 | 34.768 | 1965 | 34.289 | 1964 | 33.828 | 1963 | 33.346 | 1962 | 32.883 | 1961 | 32.409 | 1960 | 31.87 |
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