| Year | Value | | 2023 | 13,700 | | 2022 | 13,811 | | 2021 | 13,864 | | 2020 | 13,862 | | 2019 | 13,907 | | 2018 | 14,030 | | 2017 | 14,202 | | 2016 | 14,432 | | 2015 | 14,611 | | 2014 | 14,546 | | 2013 | 14,258 | | 2012 | 13,954 | | 2011 | 13,708 | | 2010 | 13,505 | | 2009 | 13,430 | | 2008 | 13,511 | | 2007 | 13,556 | | 2006 | 13,430 | | 2005 | 13,220 | | 2004 | 12,913 | | 2003 | 12,437 | | 2002 | 11,878 | | 2001 | 11,381 | | 2000 | 10,876 | | 1999 | 10,354 | | 1998 | 9,896 | | 1997 | 9,419 | | 1996 | 8,850 | | 1995 | 8,283 | | 1994 | 7,827 | | 1993 | 7,452 | | 1992 | 7,152 | | 1991 | 6,919 | | 1990 | 6,646 | | 1989 | 6,421 | | 1988 | 6,350 | | 1987 | 6,369 | | 1986 | 6,457 | | 1985 | 6,597 | | 1984 | 6,691 | | 1983 | 6,699 | | 1982 | 6,660 | | 1981 | 6,572 | | 1980 | 6,363 | | 1979 | 6,067 | | 1978 | 5,793 | | 1977 | 5,540 | | 1976 | 5,310 | | 1975 | 5,105 | | 1974 | 4,917 |
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