| Year | Value | | 2022 | 6,618 | | 2021 | 6,679 | | 2020 | 6,715 | | 2019 | 6,713 | | 2018 | 6,737 | | 2017 | 6,743 | | 2016 | 6,629 | | 2015 | 6,461 | | 2014 | 6,317 | | 2013 | 6,193 | | 2012 | 6,060 | | 2011 | 5,915 | | 2010 | 5,746 | | 2009 | 5,525 | | 2008 | 5,307 | | 2007 | 5,154 | | 2006 | 5,059 | | 2005 | 5,014 | | 2004 | 5,044 | | 2003 | 5,099 | | 2002 | 5,167 | | 2001 | 5,260 | | 2000 | 5,240 | | 1999 | 5,088 | | 1998 | 4,894 | | 1997 | 4,614 | | 1996 | 4,276 | | 1995 | 4,055 | | 1994 | 3,955 | | 1993 | 3,892 | | 1992 | 3,907 | | 1991 | 3,981 | | 1990 | 3,981 | | 1989 | 3,934 | | 1988 | 3,897 | | 1987 | 3,833 | | 1986 | 3,747 | | 1985 | 3,691 | | 1984 | 3,676 | | 1983 | 3,688 | | 1982 | 3,702 | | 1981 | 3,695 | | 1980 | 3,694 | | 1979 | 3,728 | | 1978 | 3,795 | | 1977 | 3,869 | | 1976 | 3,883 | | 1975 | 3,812 | | 1974 | 3,730 | | 1973 | 3,682 | | 1972 | 3,661 | | 1971 | 3,646 | | 1970 | 3,620 | | 1969 | 3,614 | | 1968 | 3,677 | | 1967 | 3,789 | | 1966 | 3,913 | | 1965 | 3,996 | | 1964 | 4,030 | | 1963 | 4,041 | | 1962 | 4,022 | | 1961 | 3,975 | | 1960 | 3,938 |
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