Year | Value | 2021 | 79.3 | 2020 | 79.9 | 2019 | 81.4 | 2018 | 81.2 | 2017 | 81.1 | 2016 | 81.1 | 2015 | 81.2 | 2014 | 81.3 | 2013 | 81.2 | 2012 | 81.2 | 2011 | 81.1 | 2010 | 81 | 2009 | 80.9 | 2008 | 80.6 | 2007 | 80.6 | 2006 | 80.3 | 2005 | 80.1 | 2004 | 80.1 | 2003 | 79.7 | 2002 | 79.6 | 2001 | 79.5 | 2000 | 79.3 | 1999 | 79.4 | 1998 | 79.5 | 1997 | 79.4 | 1996 | 79.1 | 1995 | 78.9 | 1994 | 79 | 1993 | 78.8 | 1992 | 79.1 | 1991 | 78.9 | 1990 | 78.8 | 1989 | 78.5 | 1988 | 78.3 | 1987 | 78.3 | 1986 | 78.2 | 1985 | 78.2 | 1984 | 78.2 | 1983 | 78.1 | 1982 | 78.1 | 1981 | 77.8 | 1980 | 77.4 | 1979 | 77.8 | 1978 | 77.3 | 1977 | 77.2 | 1976 | 76.8 | 1975 | 76.6 | 1974 | 75.9 | 1973 | 75.3 | 1972 | 75.1 | 1971 | 75 | 1970 | 74.7 | 1969 | 74.4 | 1968 | 74.1 | 1967 | 74.3 | 1966 | 73.9 | 1965 | 73.8 | 1964 | 73.7 | 1963 | 73.4 | 1962 | 73.5 | 1961 | 73.6 | 1960 | 73.1 |
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