| Year | Value | | 2022 | 9,586 | | 2021 | 9,394 | | 2020 | 9,287 | | 2019 | 9,253 | | 2018 | 9,286 | | 2017 | 9,328 | | 2016 | 9,391 | | 2015 | 9,455 | | 2014 | 9,471 | | 2013 | 9,475 | | 2012 | 9,474 | | 2011 | 9,457 | | 2010 | 9,427 | | 2009 | 9,392 | | 2008 | 9,374 | | 2007 | 9,387 | | 2006 | 9,430 | | 2005 | 9,494 | | 2004 | 9,548 | | 2003 | 9,574 | | 2002 | 9,576 | | 2001 | 9,565 | | 2000 | 9,547 | | 1999 | 9,521 | | 1998 | 9,479 | | 1997 | 9,414 | | 1996 | 9,313 | | 1995 | 9,165 | | 1994 | 8,969 | | 1993 | 8,732 | | 1992 | 8,469 | | 1991 | 8,193 | | 1990 | 7,913 | | 1989 | 7,635 | | 1988 | 7,362 | | 1987 | 7,101 | | 1986 | 6,857 | | 1985 | 6,642 | | 1984 | 6,471 | | 1983 | 6,344 | | 1982 | 6,251 | | 1981 | 6,179 | | 1980 | 6,112 | | 1979 | 6,035 | | 1978 | 5,941 | | 1977 | 5,828 | | 1976 | 5,692 | | 1975 | 5,545 | | 1974 | 5,397 | | 1973 | 5,231 | | 1972 | 5,038 | | 1971 | 4,816 | | 1970 | 4,563 | | 1969 | 4,302 | | 1968 | 4,059 | | 1967 | 3,855 | | 1966 | 3,718 | | 1965 | 3,668 | | 1964 | 3,684 | | 1963 | 3,735 | | 1962 | 3,804 | | 1961 | 3,877 | | 1960 | 3,946 |
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