Year | Value | 2021 | 2.479 | 2020 | 2.239 | 2019 | 2 | 2018 | 1.992 | 2017 | 2.039 | 2016 | 2.071 | 2015 | 2.109 | 2014 | 2.028 | 2013 | 1.933 | 2012 | 1.935 | 2011 | 1.927 | 2010 | 1.883 | 2009 | 1.925 | 2008 | 2.002 | 2007 | 2.108 | 2006 | 2.235 | 2005 | 2.308 | 2004 | 2.429 | 2003 | 2.483 | 2002 | 2.509 | 2001 | 2.516 | 2000 | 2.595 | 1999 | 2.703 | 1998 | 2.76 | 1997 | 2.75 | 1996 | 2.766 | 1995 | 2.896 | 1994 | 2.956 | 1993 | 2.989 | 1992 | 3.103 | 1991 | 3.156 | 1990 | 3.206 | 1989 | 3.24 | 1988 | 3.298 | 1987 | 3.331 | 1986 | 3.369 | 1985 | 3.415 | 1984 | 3.435 | 1983 | 3.532 | 1982 | 3.588 | 1981 | 3.686 | 1980 | 3.842 | 1979 | 4.012 | 1978 | 4.222 | 1977 | 4.412 | 1976 | 4.644 | 1975 | 4.944 | 1974 | 5.247 | 1973 | 5.601 | 1972 | 6.035 | 1971 | 6.45 | 1970 | 6.904 | 1969 | 7.324 | 1968 | 7.87 | 1967 | 8.528 | 1966 | 9.251 | 1965 | 10.032 | 1964 | 11.083 | 1963 | 12.185 | 1962 | 13.44 | 1961 | 14.72 | 1960 | 16.084 |
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