Year | Value | 2021 | 81.4 | 2020 | 80.6 | 2019 | 81.5 | 2018 | 80.9 | 2017 | 80.8 | 2016 | 80.6 | 2015 | 80.4 | 2014 | 80.4 | 2013 | 80.2 | 2012 | 79.9 | 2011 | 79.9 | 2010 | 79.5 | 2009 | 79.4 | 2008 | 79.1 | 2007 | 78.9 | 2006 | 78.7 | 2005 | 78.4 | 2004 | 78.4 | 2003 | 77.9 | 2002 | 77.7 | 2001 | 77.6 | 2000 | 77.4 | 1999 | 77.1 | 1998 | 76.9 | 1997 | 76.7 | 1996 | 76.52 | 1995 | 76.16 | 1994 | 76.06 | 1993 | 75.48 | 1992 | 75.35 | 1991 | 74.94 | 1990 | 74.81 | 1989 | 74.8 | 1988 | 74.15 | 1987 | 74.18 | 1986 | 73.98 | 1985 | 73.78 | 1984 | 73.85 | 1983 | 73.62 | 1982 | 73.42 | 1981 | 73.07 | 1980 | 72.78 | 1979 | 72.49 | 1978 | 72.43 | 1977 | 72.37 | 1976 | 72.14 | 1975 | 72.17 | 1974 | 72.2 | 1973 | 72.16 | 1972 | 72.04 | 1971 | 71.98 | 1970 | 72.22 | 1969 | 71.68 | 1968 | 71.69 | 1967 | 71.82 | 1966 | 71.82 | 1965 | 71.73 | 1964 | 71.66 | 1963 | 71.57 | 1962 | 71.37 | 1961 | 71.65 | 1960 | 71.23 |
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