| Year | Value | | 2022 | 5,006 | | 2021 | 4,844 | | 2020 | 4,754 | | 2019 | 4,804 | | 2018 | 4,743 | | 2017 | 4,626 | | 2016 | 4,686 | | 2015 | 4,702 | | 2014 | 4,686 | | 2013 | 4,666 | | 2012 | 4,674 | | 2011 | 4,677 | | 2010 | 4,634 | | 2009 | 4,606 | | 2008 | 4,595 | | 2007 | 4,546 | | 2006 | 4,461 | | 2005 | 4,375 | | 2004 | 4,390 | | 2003 | 4,529 | | 2002 | 4,691 | | 2001 | 4,987 | | 2000 | 5,463 | | 1999 | 5,921 | | 1998 | 6,328 | | 1997 | 6,597 | | 1996 | 6,697 | | 1995 | 6,748 | | 1994 | 6,800 | | 1993 | 6,820 | | 1992 | 6,799 | | 1991 | 6,783 | | 1990 | 6,744 | | 1989 | 6,685 | | 1988 | 6,633 | | 1987 | 6,557 | | 1986 | 6,430 | | 1985 | 6,256 | | 1984 | 6,061 | | 1983 | 5,891 | | 1982 | 5,750 | | 1981 | 5,641 | | 1980 | 5,596 | | 1979 | 5,571 | | 1978 | 5,552 | | 1977 | 5,507 | | 1976 | 5,367 | | 1975 | 5,178 | | 1974 | 4,959 | | 1973 | 4,746 | | 1972 | 4,657 | | 1971 | 4,592 | | 1970 | 4,509 | | 1969 | 4,470 | | 1968 | 4,430 | | 1967 | 4,382 | | 1966 | 4,342 | | 1965 | 4,297 | | 1964 | 4,222 | | 1963 | 4,145 | | 1962 | 4,071 | | 1961 | 4,006 | | 1960 | 3,962 |
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