| Year | Value | | 2023 | 3,253 | | 2022 | 3,218 | | 2021 | 3,171 | | 2020 | 3,140 | | 2019 | 3,109 | | 2018 | 3,062 | | 2017 | 3,039 | | 2016 | 3,040 | | 2015 | 3,067 | | 2014 | 3,124 | | 2013 | 3,209 | | 2012 | 3,315 | | 2011 | 3,426 | | 2010 | 3,516 | | 2009 | 3,588 | | 2008 | 3,664 | | 2007 | 3,738 | | 2006 | 3,808 | | 2005 | 3,855 | | 2004 | 3,903 | | 2003 | 3,986 | | 2002 | 4,082 | | 2001 | 4,186 | | 2000 | 4,238 | | 1999 | 4,127 | | 1998 | 3,916 | | 1997 | 3,716 | | 1996 | 3,516 | | 1995 | 3,319 | | 1994 | 3,158 | | 1993 | 3,034 | | 1992 | 2,934 | | 1991 | 2,964 | | 1990 | 3,073 | | 1989 | 3,079 | | 1988 | 2,963 | | 1987 | 2,771 | | 1986 | 2,568 | | 1985 | 2,378 | | 1984 | 2,219 | | 1983 | 2,095 | | 1982 | 1,983 | | 1981 | 1,904 | | 1980 | 1,865 | | 1979 | 1,852 | | 1978 | 1,868 | | 1977 | 1,897 | | 1976 | 1,913 | | 1975 | 1,894 | | 1974 | 1,848 |
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