| Year | Value | | 2022 | 24,666 | | 2021 | 23,600 | | 2020 | 22,585 | | 2019 | 21,444 | | 2018 | 20,164 | | 2017 | 18,801 | | 2016 | 17,593 | | 2015 | 16,594 | | 2014 | 15,765 | | 2013 | 15,255 | | 2012 | 15,015 | | 2011 | 14,784 | | 2010 | 14,547 | | 2009 | 14,349 | | 2008 | 14,220 | | 2007 | 14,148 | | 2006 | 14,105 | | 2005 | 14,065 | | 2004 | 14,019 | | 2003 | 13,962 | | 2002 | 13,880 | | 2001 | 13,760 | | 2000 | 13,590 | | 1999 | 13,347 | | 1998 | 13,009 | | 1997 | 12,622 | | 1996 | 12,279 | | 1995 | 12,032 | | 1994 | 11,867 | | 1993 | 11,786 | | 1992 | 11,732 | | 1991 | 11,572 | | 1990 | 11,234 | | 1989 | 10,753 | | 1988 | 10,154 | | 1987 | 9,473 | | 1986 | 8,808 | | 1985 | 8,225 | | 1984 | 7,711 | | 1983 | 7,235 | | 1982 | 6,810 | | 1981 | 6,439 | | 1980 | 6,124 | | 1979 | 5,870 | | 1978 | 5,694 | | 1977 | 5,582 | | 1976 | 5,518 | | 1975 | 5,506 | | 1974 | 5,556 | | 1973 | 5,669 | | 1972 | 5,816 | | 1971 | 5,920 | | 1970 | 5,923 | | 1969 | 5,815 | | 1968 | 5,598 | | 1967 | 5,317 | | 1966 | 5,086 | | 1965 | 4,968 | | 1964 | 4,951 | | 1963 | 5,030 | | 1962 | 5,181 | | 1961 | 5,325 | | 1960 | 5,415 |
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