Year | Value | 2018 | 79.645 | 2017 | 79.442 | 2016 | 79.233 | 2015 | 79.021 | 2014 | 78.81 | 2013 | 78.604 | 2012 | 78.407 | 2011 | 78.217 | 2010 | 78.036 | 2009 | 77.863 | 2008 | 77.694 | 2007 | 77.521 | 2006 | 77.339 | 2005 | 77.14 | 2004 | 76.914 | 2003 | 76.658 | 2002 | 76.37 | 2001 | 76.048 | 2000 | 75.696 | 1999 | 75.318 | 1998 | 74.923 | 1997 | 74.516 | 1996 | 74.098 | 1995 | 73.672 | 1994 | 73.233 | 1993 | 72.78 | 1992 | 72.308 | 1991 | 71.817 | 1990 | 71.304 | 1989 | 70.768 | 1988 | 70.209 | 1987 | 69.632 | 1986 | 69.04 | 1985 | 68.438 | 1984 | 67.831 | 1983 | 67.224 | 1982 | 66.621 | 1981 | 66.026 | 1980 | 65.44 | 1979 | 64.864 | 1978 | 64.295 | 1977 | 63.731 | 1976 | 63.169 | 1975 | 62.606 | 1974 | 62.038 | 1973 | 61.465 | 1972 | 60.886 | 1971 | 60.303 | 1970 | 59.722 | 1969 | 59.149 | 1968 | 58.591 | 1967 | 58.048 | 1966 | 57.519 | 1965 | 57 | 1964 | 56.481 | 1963 | 55.956 | 1962 | 55.418 | 1961 | 54.864 | 1960 | 54.295 |
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