| Year | Value | | 2024 | 9,530 | | 2023 | 9,555 | | 2022 | 9,579 | | 2021 | 9,601 | | 2020 | 9,616 | | 2019 | 9,614 | | 2018 | 9,598 | | 2017 | 9,572 | | 2016 | 9,542 | | 2015 | 9,501 | | 2014 | 9,426 | | 2013 | 9,337 | | 2012 | 9,386 | | 2011 | 9,579 | | 2010 | 9,772 | | 2009 | 9,959 | | 2008 | 10,139 | | 2007 | 10,316 | | 2006 | 10,496 | | 2005 | 10,647 | | 2004 | 10,686 | | 2003 | 10,639 | | 2002 | 10,589 | | 2001 | 10,539 | | 2000 | 10,464 | | 1999 | 10,294 | | 1998 | 10,042 | | 1997 | 9,770 | | 1996 | 9,480 | | 1995 | 9,214 | | 1994 | 8,989 | | 1993 | 8,781 | | 1992 | 8,583 | | 1991 | 8,390 | | 1990 | 8,211 | | 1989 | 8,038 | | 1988 | 7,858 | | 1987 | 7,670 | | 1986 | 7,481 | | 1985 | 7,270 | | 1984 | 7,047 | | 1983 | 6,838 | | 1982 | 6,638 | | 1981 | 6,453 | | 1980 | 6,365 | | 1979 | 6,399 | | 1978 | 6,463 | | 1977 | 6,515 | | 1976 | 6,557 | | 1975 | 6,594 |
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