| Year | Value | | 2024 | 17,560 | | 2023 | 17,069 | | 2022 | 16,543 | | 2021 | 16,054 | | 2020 | 15,052 | | 2019 | 13,661 | | 2018 | 12,666 | | 2017 | 12,051 | | 2016 | 11,777 | | 2015 | 12,196 | | 2014 | 13,010 | | 2013 | 13,686 | | 2012 | 14,194 | | 2011 | 14,509 | | 2010 | 14,506 | | 2009 | 14,189 | | 2008 | 13,779 | | 2007 | 13,398 | | 2006 | 13,058 | | 2005 | 12,753 | | 2004 | 12,504 | | 2003 | 12,300 | | 2002 | 12,098 | | 2001 | 11,905 | | 2000 | 11,661 | | 1999 | 11,362 | | 1998 | 10,942 | | 1997 | 10,435 | | 1996 | 9,913 | | 1995 | 9,407 | | 1994 | 8,866 | | 1993 | 8,218 | | 1992 | 7,507 | | 1991 | 6,852 | | 1990 | 6,383 | | 1989 | 6,239 | | 1988 | 6,546 | | 1987 | 7,298 | | 1986 | 8,232 | | 1985 | 9,005 | | 1984 | 9,373 | | 1983 | 9,220 | | 1982 | 8,639 | | 1981 | 7,955 | | 1980 | 7,424 | | 1979 | 7,087 | | 1978 | 6,931 | | 1977 | 6,914 | | 1976 | 6,943 | | 1975 | 6,932 |
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