Year | Value | 2017 | 81.5 | 2016 | 81.1 | 2015 | 81.2 | 2014 | 81.1 | 2013 | 80.9 | 2012 | 80.7 | 2011 | 80.7 | 2009 | 80.1 | 2008 | 79.1 | 2007 | 79 | 2006 | 78.5 | 2005 | 76.602 | 2004 | 76.456 | 2003 | 76.314 | 2002 | 76.15 | 2001 | 76.019 | 2000 | 75.871 | 1999 | 75.749 | 1998 | 75.659 | 1997 | 75.489 | 1996 | 75.388 | 1995 | 75.254 | 1994 | 75.233 | 1993 | 75.078 | 1992 | 74.977 | 1991 | 74.903 | 1990 | 74.775 | 1989 | 74.399 | 1988 | 74.529 | 1987 | 74.406 | 1986 | 74.055 | 1985 | 73.884 | 1984 | 73.821 | 1983 | 73.708 | 1982 | 73.547 | 1981 | 73.433 | 1980 | 73.302 | 1979 | 73.155 | 1978 | 72.993 | 1977 | 72.53 | 1976 | 72.419 | 1975 | 72.251 | 1974 | 72.132 | 1973 | 71.557 | 1972 | 71.379 | 1971 | 70.819 | 1970 | 70.624 | 1969 | 70.409 | 1968 | 69.95 | 1967 | 69.781 | 1966 | 69.651 | 1965 | 69.249 | 1964 | 69.1 | 1963 | 68.897 | 1962 | 68.466 | 1961 | 68.291 | 1960 | 68.108 |
|