| Year | Value | | 2022 | 9,570 | | 2021 | 9,457 | | 2020 | 9,252 | | 2019 | 9,046 | | 2018 | 8,930 | | 2017 | 8,952 | | 2016 | 9,116 | | 2015 | 9,323 | | 2014 | 9,492 | | 2013 | 9,542 | | 2012 | 9,444 | | 2011 | 9,286 | | 2010 | 9,193 | | 2009 | 9,228 | | 2008 | 9,405 | | 2007 | 9,631 | | 2006 | 9,727 | | 2005 | 9,678 | | 2004 | 9,584 | | 2003 | 9,472 | | 2002 | 9,366 | | 2001 | 9,393 | | 2000 | 9,610 | | 1999 | 9,905 | | 1998 | 10,210 | | 1997 | 10,580 | | 1996 | 10,946 | | 1995 | 11,202 | | 1994 | 11,337 | | 1993 | 11,388 | | 1992 | 11,414 | | 1991 | 11,465 | | 1990 | 11,606 | | 1989 | 11,852 | | 1988 | 12,178 | | 1987 | 12,572 | | 1986 | 12,997 | | 1985 | 13,408 | | 1984 | 13,758 | | 1983 | 14,008 | | 1982 | 14,132 | | 1981 | 14,117 | | 1980 | 13,969 | | 1979 | 13,681 | | 1978 | 13,289 | | 1977 | 12,858 | | 1976 | 12,411 | | 1975 | 11,969 | | 1974 | 11,466 | | 1973 | 10,966 | | 1972 | 10,525 | | 1971 | 10,076 | | 1970 | 9,613 | | 1969 | 9,225 | | 1968 | 8,866 | | 1967 | 8,473 | | 1966 | 8,128 | | 1965 | 7,864 | | 1964 | 7,699 | | 1963 | 7,633 | | 1962 | 7,701 | | 1961 | 7,912 | | 1960 | 8,140 |
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