| Year | Value | | 2022 | 9,206 | | 2021 | 9,281 | | 2020 | 9,212 | | 2019 | 9,115 | | 2018 | 9,008 | | 2017 | 8,889 | | 2016 | 8,871 | | 2015 | 8,975 | | 2014 | 9,102 | | 2013 | 9,231 | | 2012 | 9,428 | | 2011 | 9,657 | | 2010 | 9,804 | | 2009 | 9,879 | | 2008 | 9,915 | | 2007 | 9,896 | | 2006 | 9,881 | | 2005 | 9,937 | | 2004 | 10,098 | | 2003 | 10,332 | | 2002 | 10,529 | | 2001 | 10,659 | | 2000 | 10,808 | | 1999 | 10,945 | | 1998 | 10,965 | | 1997 | 10,933 | | 1996 | 10,878 | | 1995 | 10,744 | | 1994 | 10,557 | | 1993 | 10,336 | | 1992 | 10,070 | | 1991 | 9,753 | | 1990 | 9,406 | | 1989 | 9,092 | | 1988 | 8,819 | | 1987 | 8,530 | | 1986 | 8,194 | | 1985 | 7,787 | | 1984 | 7,345 | | 1983 | 6,854 | | 1982 | 6,304 | | 1981 | 5,773 | | 1980 | 5,299 | | 1979 | 4,927 | | 1978 | 4,673 | | 1977 | 4,555 | | 1976 | 4,585 | | 1975 | 4,726 | | 1974 | 4,962 | | 1973 | 5,271 | | 1972 | 5,576 | | 1971 | 5,809 | | 1970 | 5,957 | | 1969 | 6,013 | | 1968 | 5,978 | | 1967 | 5,875 | | 1966 | 5,750 | | 1965 | 5,645 | | 1964 | 5,566 | | 1963 | 5,497 | | 1962 | 5,468 | | 1961 | 5,525 | | 1960 | 5,697 |
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