| Year | Value | | 2022 | 0.55609146008218 | | 2021 | 0.45397664568484 | | 2020 | 0.2128462204393 | | 2019 | 0.057797146691196 | | 2018 | 0.0025026999236922 | | 2017 | 0.070534837662764 | | 2016 | 0.12758974279473 | | 2015 | 0.17896510593018 | | 2014 | 0.23039758952504 | | 2013 | 0.26242648707266 | | 2012 | 0.297238780271 | | 2011 | 0.35136047581481 | | 2010 | 0.41914160707166 | | 2009 | 0.51743219609332 | | 2008 | 0.68066408809922 | | 2007 | 0.85300937635266 | | 2006 | 0.92833114360568 | | 2005 | 0.94499091797119 | | 2004 | 0.97252940431947 | | 2003 | 0.98525732950846 | | 2002 | 1.013601896052 | | 2001 | 1.0528054399903 | | 2000 | 1.0975205143768 | | 1999 | 1.157357414556 | | 1998 | 1.1584794308059 | | 1997 | 1.0035622071833 | | 1996 | 0.54028872907971 | | 1995 | 0.18230647309827 | | 1994 | 0.20316449825842 | | 1993 | 0.29681689396015 | | 1992 | 0.25793888542267 | | 1991 | 0.56246323047673 | | 1990 | 0.99489982553605 | | 1989 | 1.0844086451296 | | 1988 | 1.2628298852371 | | 1987 | 1.6188023623679 | | 1986 | 2.0675253290836 | | 1985 | 2.350559047776 | | 1984 | 2.4169465740289 | | 1983 | 2.4262805879833 | | 1982 | 2.4428602077158 | | 1981 | 2.4591880488899 | | 1980 | 2.4694978467489 | | 1979 | 2.4545889349197 | | 1978 | 2.3617224332142 | | 1977 | 2.1388862902109 | | 1976 | 1.8587764635882 | | 1975 | 1.6650415309641 | | 1974 | 1.6113704653002 | | 1973 | 1.687756433277 | | 1972 | 1.8267080553296 | | 1971 | 1.9455698635304 | | 1970 | 2.0452834655146 | | 1969 | 2.1454860421385 | | 1968 | 2.2681114709046 | | 1967 | 2.5127474794894 | | 1966 | 2.806248676542 | | 1965 | 2.9856452129641 | | 1964 | 3.0850127587798 | | 1963 | 3.1507185735844 | | 1962 | 3.1255326977952 | | 1961 | 3.1098509758004 |
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