Year | Value | 2022 | 25.584 | 2021 | 25.128 | 2020 | 24.67 | 2019 | 24.21 | 2018 | 23.749 | 2017 | 23.286 | 2016 | 22.823 | 2015 | 22.36 | 2014 | 21.896 | 2013 | 21.433 | 2012 | 20.97 | 2011 | 20.508 | 2010 | 20.048 | 2009 | 19.589 | 2008 | 19.138 | 2007 | 18.694 | 2006 | 18.259 | 2005 | 17.832 | 2004 | 17.413 | 2003 | 17.001 | 2002 | 16.597 | 2001 | 16.201 | 2000 | 15.813 | 1999 | 15.496 | 1998 | 15.285 | 1997 | 15.076 | 1996 | 14.869 | 1995 | 14.664 | 1994 | 14.462 | 1993 | 14.262 | 1992 | 14.065 | 1991 | 13.87 | 1990 | 13.677 | 1989 | 13.486 | 1988 | 13.298 | 1987 | 13.111 | 1986 | 12.837 | 1985 | 12.433 | 1984 | 12.041 | 1983 | 11.659 | 1982 | 11.288 | 1981 | 10.927 | 1980 | 10.576 | 1979 | 10.235 | 1978 | 9.904 | 1977 | 9.583 | 1976 | 9.271 | 1975 | 9.125 | 1974 | 9.083 | 1973 | 9.041 | 1972 | 8.999 | 1971 | 8.958 | 1970 | 8.917 | 1969 | 8.67 | 1968 | 8.292 | 1967 | 7.928 | 1966 | 7.579 | 1965 | 7.245 | 1964 | 6.924 | 1963 | 6.616 | 1962 | 6.321 | 1961 | 6.038 | 1960 | 5.768 |
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