Year | Value | 2021 | 71.7 | 2020 | 72.5 | 2019 | 74.1 | 2018 | 73.7 | 2017 | 73.9 | 2016 | 73.9 | 2015 | 73.5 | 2014 | 73.7 | 2013 | 73 | 2012 | 72.6 | 2011 | 72.5 | 2010 | 72.1 | 2009 | 71.5 | 2008 | 71.3 | 2007 | 71 | 2006 | 70.9 | 2005 | 70.8 | 2004 | 70.7 | 2003 | 70.5 | 2002 | 70.4 | 2001 | 70.2 | 2000 | 69.7 | 1999 | 68.8 | 1998 | 68.9 | 1997 | 68.5 | 1996 | 68.1 | 1995 | 67.6 | 1994 | 67.5 | 1993 | 67.4 | 1992 | 66.7 | 1991 | 66.1 | 1990 | 66.5 | 1989 | 66.8 | 1988 | 67.2 | 1987 | 66.8 | 1986 | 66.8 | 1985 | 66.5 | 1984 | 66.8 | 1983 | 67 | 1982 | 67.2 | 1981 | 67.1 | 1980 | 66 | 1979 | 66.8 | 1978 | 66.4 | 1977 | 66.5 | 1976 | 66.9 | 1975 | 67 | 1974 | 67.8 | 1973 | 67.2 | 1972 | 67.3 | 1971 | 66.1 | 1970 | 66.6 | 1969 | 66.5 | 1968 | 67 | 1967 | 66.4 | 1966 | 66.9 | 1965 | 66.6 | 1964 | 65.8 | 1963 | 65.4 | 1962 | 64.5 | 1961 | 64.9 | 1960 | 64.9 |
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