Year | Value | 2021 | 19.041713641488 | 2020 | 19.041713641488 | 2019 | 19.041713641488 | 2018 | 19.041713641488 | 2017 | 19.594137542277 | 2016 | 20.11273957159 | 2015 | 20.631341600902 | 2014 | 21.149943630214 | 2013 | 21.668545659527 | 2012 | 22.187147688839 | 2011 | 22.040586245772 | 2010 | 21.860202931229 | 2009 | 21.679819616685 | 2008 | 21.499436302142 | 2007 | 21.30777903044 | 2006 | 22.074408117249 | 2005 | 22.818489289741 | 2004 | 23.562570462232 | 2003 | 24.306651634724 | 2002 | 25.028184892897 | 2001 | 26.459977452086 | 2000 | 27.869222096956 | 1999 | 29.301014656144 | 1998 | 30.721533258174 | 1997 | 32.807215332582 | 1996 | 34.836527621195 | 1995 | 34.836527621195 | 1994 | 34.836527621195 | 1993 | 35.062006764374 | 1992 | 46.223224351747 | 1991 | 47.350620067644 | 1990 | 49.041713641488 | 1989 | 50.732807215333 | 1988 | 52.085682074408 | 1987 | 52.085682074408 | 1986 | 52.198421645998 | 1985 | 51.972942502818 | 1984 | 52.311161217587 | 1983 | 52.536640360767 | 1982 | 52.649379932356 | 1981 | 52.649379932356 | 1980 | 53.551296505073 | 1979 | 54.791431792559 | 1978 | 55.806087936866 | 1977 | 55.355129650507 | 1976 | 55.580608793687 | 1975 | 55.580608793687 | 1974 | 55.693348365276 | 1973 | 55.467869222097 | 1972 | 58.060879368658 | 1971 | 59.751972942503 | 1970 | 62.232243517475 | 1969 | 63.359639233371 | 1968 | 63.810597519729 | 1967 | 64.036076662909 | 1966 | 65.501691093574 | 1965 | 68.658399098083 | 1964 | 65.952649379932 | 1963 | 68.207440811725 | 1962 | 67.756482525366 | 1961 | 69.447576099211 |
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