| Year | Value | | 2022 | 7,174 | | 2021 | 7,310 | | 2020 | 7,495 | | 2019 | 7,713 | | 2018 | 7,934 | | 2017 | 8,168 | | 2016 | 8,332 | | 2015 | 8,432 | | 2014 | 8,448 | | 2013 | 8,335 | | 2012 | 8,130 | | 2011 | 7,889 | | 2010 | 7,653 | | 2009 | 7,556 | | 2008 | 7,679 | | 2007 | 7,862 | | 2006 | 8,102 | | 2005 | 8,384 | | 2004 | 8,662 | | 2003 | 8,879 | | 2002 | 9,018 | | 2001 | 9,051 | | 2000 | 8,985 | | 1999 | 8,906 | | 1998 | 8,868 | | 1997 | 8,872 | | 1996 | 8,897 | | 1995 | 8,882 | | 1994 | 8,737 | | 1993 | 8,537 | | 1992 | 8,354 | | 1991 | 8,138 | | 1990 | 7,926 | | 1989 | 7,853 | | 1988 | 7,796 | | 1987 | 7,678 | | 1986 | 7,596 | | 1985 | 7,535 | | 1984 | 7,475 | | 1983 | 7,376 | | 1982 | 7,229 | | 1981 | 7,048 | | 1980 | 6,835 | | 1979 | 6,715 | | 1978 | 6,724 | | 1977 | 6,779 | | 1976 | 6,854 | | 1975 | 6,897 | | 1974 | 6,830 | | 1973 | 6,657 | | 1972 | 6,468 | | 1971 | 6,277 | | 1970 | 6,130 | | 1969 | 6,112 | | 1968 | 6,158 | | 1967 | 6,157 | | 1966 | 6,124 | | 1965 | 6,066 | | 1964 | 5,986 | | 1963 | 5,879 | | 1962 | 5,740 | | 1961 | 5,560 | | 1960 | 5,342 |
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