Year | Value | 2021 | 79.9 | 2020 | 79.7 | 2019 | 80.6 | 2018 | 80.3 | 2017 | 80.2 | 2016 | 80 | 2015 | 79.9 | 2014 | 80 | 2013 | 79.5 | 2012 | 79.3 | 2011 | 79.4 | 2010 | 78.8 | 2009 | 78.5 | 2008 | 78.3 | 2007 | 78 | 2006 | 77.6 | 2005 | 77.2 | 2004 | 76.9 | 2003 | 76.2 | 2002 | 76 | 2001 | 75.8 | 2000 | 75.5 | 1999 | 75.3 | 1998 | 75.2 | 1997 | 75.17 | 1996 | 74.66 | 1995 | 74.59 | 1994 | 74.58 | 1993 | 73.98 | 1992 | 74.3 | 1991 | 74 | 1990 | 73.8 | 1989 | 73.7 | 1988 | 73.7 | 1987 | 73.51 | 1986 | 73.09 | 1985 | 73.07 | 1984 | 72.96 | 1983 | 72.93 | 1982 | 72.73 | 1981 | 72.71 | 1980 | 72.47 | 1979 | 72.45 | 1978 | 71.95 | 1977 | 72.08 | 1976 | 71.53 | 1975 | 71.45 | 1974 | 71.61 | 1973 | 71.3 | 1972 | 70.81 | 1971 | 70.99 | 1970 | 70.81 | 1969 | 70.92 | 1968 | 70.92 | 1967 | 71.17 | 1966 | 71.03 | 1965 | 71.12 | 1964 | 71.27 | 1963 | 71.02 | 1962 | 71.08 | 1961 | 71.56 | 1960 | 71.5 |
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