Year | Value | 2021 | 2.02 | 2020 | 2.04 | 2019 | 2.1 | 2018 | 2.06 | 2017 | 2.04 | 2016 | 2.13 | 2015 | 2.08 | 2014 | 2.17 | 2013 | 2.19 | 2012 | 2.28 | 2011 | 2.15 | 2010 | 2.2 | 2009 | 2.2 | 2008 | 2.2 | 2007 | 2.2 | 2006 | 2.29 | 2005 | 2.2 | 2004 | 2.18 | 2003 | 2.27 | 2002 | 2.33 | 2001 | 2.43 | 2000 | 2.59 | 1999 | 2.48 | 1998 | 2.54 | 1997 | 2.67 | 1996 | 2.65 | 1995 | 2.59 | 1994 | 2.7 | 1993 | 2.86 | 1992 | 2.99 | 1991 | 3.15 | 1990 | 3.18 | 1989 | 2.97 | 1988 | 3.1 | 1987 | 3.25 | 1986 | 3.17 | 1985 | 3 | 1984 | 3.17 | 1983 | 3.33 | 1982 | 3.42 | 1981 | 3.64 | 1980 | 3.424 | 1979 | 3.426 | 1978 | 3.428 | 1977 | 3.43 | 1976 | 3.6 | 1975 | 3.7 | 1974 | 3.8 | 1973 | 3.9 | 1972 | 4.1 | 1971 | 4.2 | 1970 | 4.3 | 1969 | 4.59 | 1968 | 4.88 | 1967 | 5.17 | 1966 | 5.385 | 1965 | 5.6 | 1964 | 5.7 | 1963 | 5.9 | 1962 | 6.01 | 1961 | 6.144 | 1960 | 6.278 |
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