| Year | Value | | 2024 | 17,419 | | 2023 | 17,377 | | 2022 | 17,262 | | 2021 | 17,099 | | 2020 | 16,800 | | 2019 | 16,281 | | 2018 | 15,491 | | 2017 | 14,608 | | 2016 | 13,793 | | 2015 | 12,660 | | 2014 | 11,346 | | 2013 | 10,473 | | 2012 | 9,912 | | 2011 | 9,659 | | 2010 | 10,089 | | 2009 | 10,902 | | 2008 | 11,628 | | 2007 | 12,225 | | 2006 | 12,601 | | 2005 | 12,715 | | 2004 | 12,630 | | 2003 | 12,373 | | 2002 | 12,022 | | 2001 | 11,723 | | 2000 | 11,448 | | 1999 | 11,253 | | 1998 | 11,138 | | 1997 | 11,072 | | 1996 | 10,902 | | 1995 | 10,555 | | 1994 | 10,035 | | 1993 | 9,400 | | 1992 | 8,725 | | 1991 | 8,094 | | 1990 | 7,542 | | 1989 | 7,022 | | 1988 | 6,444 | | 1987 | 5,818 | | 1986 | 5,231 | | 1985 | 4,784 | | 1984 | 4,596 | | 1983 | 4,748 | | 1982 | 5,195 | | 1981 | 5,788 | | 1980 | 6,396 | | 1979 | 6,893 | | 1978 | 7,162 | | 1977 | 7,196 | | 1976 | 7,077 | | 1975 | 6,860 |
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