Year | Value | 2021 | 69.65 | 2020 | 69.71 | 2019 | 70.19 | 2018 | 69.75 | 2017 | 68.69 | 2016 | 69.23 | 2015 | 70.27 | 2014 | 70.01 | 2013 | 69.31 | 2012 | 68.35 | 2011 | 67.42 | 2010 | 67.97 | 2009 | 68.45 | 2008 | 67.82 | 2007 | 67.04 | 2006 | 66.08 | 2005 | 65.52 | 2004 | 66 | 2003 | 65.72 | 2002 | 64.87 | 2001 | 64.33 | 2000 | 63.33 | 1999 | 63.84 | 1998 | 63.44 | 1997 | 63.12 | 1996 | 63.26 | 1995 | 63.41 | 1994 | 63.34 | 1993 | 62.8 | 1992 | 62.04 | 1991 | 61.7 | 1990 | 61.4 | 1989 | 60.77 | 1988 | 60.68 | 1987 | 61.02 | 1986 | 61 | 1985 | 60.58 | 1984 | 60.53 | 1983 | 60.5 | 1982 | 60.1 | 1981 | 59.47 | 1980 | 59.84 | 1979 | 60.35 | 1978 | 60 |
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