| Year | Value | | 2022 | 0.9604965589084 | | 2021 | 0.40539615377627 | | 2020 | 0.34386283545216 | | 2019 | 0.50807504167565 | | 2018 | 0.49893165753075 | | 2017 | 0.5414689539293 | | 2016 | 0.59239614359816 | | 2015 | 0.607238212488 | | 2014 | 0.59357995058389 | | 2013 | 0.58656122212245 | | 2012 | 0.53649151454589 | | 2011 | 0.59344667655409 | | 2010 | 0.58677704627641 | | 2009 | 0.4947745594458 | | 2008 | 0.40885126457577 | | 2007 | 0.18911545050202 | | 2006 | 0.18896323742119 | | 2005 | 0.14642004905856 | | 2004 | 0.12426455483944 | | 2003 | 0.071287897043689 | | 2002 | 0.018476601059774 | | 2001 | 0.025087266576818 | | 2000 | 0.026838178915781 | | 1999 | 0.011967637582401 | | 1998 | 0.085005429741898 | | 1997 | 0.16642810267686 | | 1996 | 0.20488048705572 | | 1995 | 0.14959430021546 | | 1994 | 0.2286571843884 | | 1993 | 0.34049769370578 | | 1992 | 0.51440432552661 | | 1991 | 0.70008172436448 | | 1990 | 0.67432810001453 | | 1989 | 0.87399243637718 | | 1988 | 1.0708471880336 | | 1987 | 1.1070456543803 | | 1986 | 1.1027590971878 | | 1985 | 1.1124849666699 | | 1984 | 1.128168652387 | | 1983 | 1.0560184865773 | | 1982 | 1.0282037181102 | | 1981 | 1.0472975153322 | | 1980 | 1.0613898970403 | | 1979 | 1.0590844698988 | | 1978 | 1.0746983823214 | | 1977 | 1.0949950828093 | | 1976 | 1.0878109084878 | | 1975 | 1.0408942663568 | | 1974 | 1.0684530982237 | | 1973 | 1.0794647435621 | | 1972 | 1.0974111214538 | | 1971 | 1.0874034049394 | | 1970 | 1.1029864229063 | | 1969 | 1.1770978396829 | | 1968 | 1.2224129178871 | | 1967 | 1.2474550250354 | | 1966 | 1.2514609476277 | | 1965 | 1.5151070667567 | | 1964 | 1.574268794257 | | 1963 | 1.5995745533901 | | 1962 | 1.6280116447406 | | 1961 | 1.6523253325281 |
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