| Year | Value | | 2024 | 38,808 | | 2023 | 37,116 | | 2022 | 36,354 | | 2021 | 35,578 | | 2020 | 34,846 | | 2019 | 33,933 | | 2018 | 32,965 | | 2017 | 32,153 | | 2016 | 31,600 | | 2015 | 31,255 | | 2014 | 31,099 | | 2013 | 31,243 | | 2012 | 31,715 | | 2011 | 32,426 | | 2010 | 33,350 | | 2009 | 34,507 | | 2008 | 35,727 | | 2007 | 36,685 | | 2006 | 36,608 | | 2005 | 35,441 | | 2004 | 33,716 | | 2003 | 31,509 | | 2002 | 28,992 | | 2001 | 27,228 | | 2000 | 26,340 | | 1999 | 25,500 | | 1998 | 24,795 | | 1997 | 24,243 | | 1996 | 23,973 | | 1995 | 23,851 | | 1994 | 24,521 | | 1993 | 25,888 | | 1992 | 26,799 | | 1991 | 27,164 | | 1990 | 27,282 | | 1989 | 25,856 | | 1988 | 23,068 | | 1987 | 21,023 | | 1986 | 19,763 | | 1985 | 18,750 | | 1984 | 17,809 | | 1983 | 16,970 | | 1982 | 16,225 | | 1981 | 15,584 | | 1980 | 15,072 | | 1979 | 14,744 | | 1978 | 14,511 | | 1977 | 14,225 | | 1976 | 13,916 | | 1975 | 13,625 |
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