Year | Value | 2021 | 81.4 | 2020 | 81.1 | 2019 | 80.8 | 2018 | 80.4 | 2017 | 80.1 | 2016 | 79.8 | 2015 | 79.5 | 2014 | 79.3 | 2013 | 79.1 | 2012 | 78.8 | 2011 | 78.5 | 2010 | 78.1 | 2009 | 77.8 | 2008 | 77.5 | 2007 | 77.5 | 2006 | 77.2 | 2005 | 76.9 | 2004 | 76.8 | 2003 | 76.7 | 2002 | 76.6 | 2001 | 76.3 | 2000 | 75.9 | 1999 | 75.5 | 1998 | 75.1 | 1997 | 74.7 | 1996 | 74.3 | 1995 | 74 | 1994 | 73.8 | 1993 | 73.5 | 1992 | 73.2 | 1991 | 72.9 | 1990 | 72.7 | 1989 | 72.5 | 1988 | 72.3 | 1987 | 72.1 | 1986 | 71.9 | 1978 | 73.4 | 1973 | 72.4 |
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