Year | Value | 2021 | 78.7 | 2020 | 78.4 | 2019 | 79.6 | 2018 | 79.5 | 2017 | 79.5 | 2016 | 79.4 | 2015 | 79.2 | 2014 | 79.5 | 2013 | 79.2 | 2012 | 79.1 | 2011 | 79 | 2010 | 78.5 | 2009 | 78.1 | 2008 | 77.6 | 2007 | 77.4 | 2006 | 77.2 | 2005 | 77 | 2004 | 76.6 | 2003 | 76.3 | 2002 | 75.9 | 2001 | 75.7 | 2000 | 75.4 | 1999 | 75 | 1998 | 74.8 | 1997 | 74.65 | 1996 | 74.6 | 1995 | 74.3 | 1994 | 74.3 | 1993 | 73.8 | 1992 | 73.8 | 1991 | 73.4 | 1990 | 73.1 | 1989 | 72.9 | 1988 | 72.6 | 1987 | 72.5 | 1986 | 72.1 | 1985 | 71.8 | 1984 | 71.9 | 1983 | 71.5 | 1982 | 71.3 | 1981 | 71.1 | 1980 | 70.7 | 1979 | 70.3 | 1978 | 70.2 | 1977 | 70.2 | 1976 | 69.8 | 1975 | 69.7 | 1974 | 69.5 | 1973 | 69.3 | 1972 | 69.1 | 1971 | 69.2 | 1970 | 68.9 | 1969 | 68.6 | 1968 | 68.7 | 1967 | 69.1 | 1966 | 68.5 | 1965 | 68.6 | 1964 | 68.6 | 1963 | 67.9 | 1962 | 68 | 1961 | 68 | 1960 | 68.2 |
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