Year | Value | 2021 | 5.602932 | 2020 | 6.546656 | 2019 | 13.092473 | 2018 | 13.234265 | 2017 | 12.124027 | 2016 | 8.096 | 2015 | 10.35424112 | 2014 | 13.28618 | 2013 | 14.683452 | 2012 | 15.599081223435 | 2011 | 12.729069270331 | 2010 | 14.640172 | 2009 | 13.927 | 2008 | 15.381 | 2007 | 15.344 | 2006 | 18.572 | 2005 | 18.048 | 2004 | 20.291 | 2003 | 19.236 | 2002 | 19.189 | 2001 | 20.106 | 2000 | 20.818 | 1999 | 19.2000007629 | 1998 | 20.2999992371 | 1997 | 18.7000007629 | 1996 | 18.3999996185 | 1995 | 18.6000003815 | 1994 | 17.2999992371 | 1993 | 16.3999996185 | 1992 | 16.2000007629 | 1991 | 17.7999992371 | 1990 | 19.1000003815 | 1989 | 18.7999992371 | 1988 | 16.7999992371 | 1987 | 18.7000007629 | 1986 | 14.6000003815 | 1985 | 15.8999996185 | 1984 | 18.2999992371 | 1983 | 19.5 | 1982 | 16.3999996185 | 1981 | 13.3999996185 | 1980 | 11.6000003815 | 1979 | 11 | 1978 | 10.1000003815 | 1977 | 8.1999998093 | 1976 | 6.6999998093 | 1975 | 5.6999998093 | 1974 | 5.0999999046 | 1973 | 3.7999999523 | 1972 | 2.7999999523 | 1971 | 1.6000000238 | 1970 | 1.3999999762 |
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