| Year | Value | | 2022 | 5,874 | | 2021 | 5,836 | | 2020 | 5,778 | | 2019 | 5,790 | | 2018 | 5,880 | | 2017 | 6,007 | | 2016 | 6,113 | | 2015 | 6,163 | | 2014 | 6,179 | | 2013 | 6,150 | | 2012 | 6,110 | | 2011 | 6,108 | | 2010 | 6,087 | | 2009 | 6,029 | | 2008 | 5,947 | | 2007 | 5,851 | | 2006 | 5,812 | | 2005 | 5,874 | | 2004 | 6,010 | | 2003 | 6,208 | | 2002 | 6,444 | | 2001 | 6,660 | | 2000 | 6,784 | | 1999 | 6,751 | | 1998 | 6,609 | | 1997 | 6,445 | | 1996 | 6,302 | | 1995 | 6,198 | | 1994 | 6,058 | | 1993 | 5,885 | | 1992 | 5,765 | | 1991 | 5,663 | | 1990 | 5,549 | | 1989 | 5,444 | | 1988 | 5,338 | | 1987 | 5,203 | | 1986 | 5,037 | | 1985 | 4,868 | | 1984 | 4,710 | | 1983 | 4,566 | | 1982 | 4,428 | | 1981 | 4,296 | | 1980 | 4,168 | | 1979 | 4,043 | | 1978 | 3,919 | | 1977 | 3,804 | | 1976 | 3,697 | | 1975 | 3,586 | | 1974 | 3,473 | | 1973 | 3,366 | | 1972 | 3,271 | | 1971 | 3,184 | | 1970 | 3,098 | | 1969 | 2,968 | | 1968 | 2,804 | | 1967 | 2,643 | | 1966 | 2,484 | | 1965 | 2,333 | | 1964 | 2,231 | | 1963 | 2,173 | | 1962 | 2,115 | | 1961 | 2,052 | | 1960 | 1,988 |
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