| Year | Value | | 2022 | 28,506 | | 2021 | 27,207 | | 2020 | 26,059 | | 2019 | 24,440 | | 2018 | 22,476 | | 2017 | 20,940 | | 2016 | 19,708 | | 2015 | 18,562 | | 2014 | 17,602 | | 2013 | 16,842 | | 2012 | 16,173 | | 2011 | 15,789 | | 2010 | 15,712 | | 2009 | 15,623 | | 2008 | 15,426 | | 2007 | 15,130 | | 2006 | 14,814 | | 2005 | 14,451 | | 2004 | 13,948 | | 2003 | 13,439 | | 2002 | 13,054 | | 2001 | 12,719 | | 2000 | 12,403 | | 1999 | 12,311 | | 1998 | 12,449 | | 1997 | 12,739 | | 1996 | 13,109 | | 1995 | 13,655 | | 1994 | 14,178 | | 1993 | 14,473 | | 1992 | 14,692 | | 1991 | 14,832 | | 1990 | 14,555 | | 1989 | 14,424 | | 1988 | 14,314 | | 1987 | 14,109 | | 1986 | 13,850 | | 1985 | 13,546 | | 1984 | 13,428 | | 1983 | 13,681 | | 1982 | 13,782 | | 1981 | 13,749 | | 1980 | 13,756 | | 1979 | 13,431 | | 1978 | 12,880 | | 1977 | 12,114 | | 1976 | 11,198 | | 1975 | 10,217 | | 1974 | 9,299 | | 1973 | 8,583 | | 1972 | 8,098 | | 1971 | 7,924 | | 1970 | 7,976 | | 1969 | 8,187 | | 1968 | 8,471 | | 1967 | 8,699 | | 1966 | 8,801 | | 1965 | 8,768 | | 1964 | 8,652 | | 1963 | 8,514 | | 1962 | 8,440 | | 1961 | 8,470 | | 1960 | 8,598 |
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