Year | Value | 2021 | 4.85 | 2020 | 4.8 | 2019 | 4.75 | 2018 | 4.7 | 2017 | 4.65 | 2016 | 4.6 | 2015 | 4.55 | 2014 | 4.5 | 2013 | 4.45 | 2012 | 4.4 | 2011 | 4.35 | 2010 | 4.3 | 2009 | 4.25 | 2008 | 4.2 | 2007 | 4.15 | 2006 | 4.1 | 2005 | 4.05 | 2004 | 4 | 2003 | 3.95 | 2002 | 3.9 | 2001 | 3.85 | 2000 | 3.8 | 1999 | 3.75 | 1998 | 3.65 | 1997 | 3.6 | 1996 | 3.55 | 1995 | 3.5 | 1994 | 3.45 | 1993 | 3.4 | 1992 | 3.35 | 1991 | 3.25 | 1990 | 3.2 | 1989 | 3.2 | 1988 | 3.2 | 1987 | 3.2 | 1986 | 3.2 | 1985 | 3.2 | 1984 | 3.2 | 1983 | 3.2 | 1982 | 3.2 | 1981 | 3.2 | 1980 | 3.2 | 1979 | 3.2 | 1978 | 3.2 | 1977 | 3.2 | 1976 | 3.2 | 1975 | 3.2 | 1974 | 3.2 | 1973 | 3.2 | 1972 | 3.2 | 1971 | 3.2 | 1970 | 3.2 | 1969 | 3.2 | 1968 | 3.2 | 1967 | 3.2 | 1966 | 3.2 | 1965 | 3.2 | 1964 | 3.2 | 1963 | 3.2 | 1962 | 3.2 | 1961 | 3.2 |
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