| Year | Value | | 2022 | 15,955 | | 2021 | 15,246 | | 2020 | 14,915 | | 2019 | 14,597 | | 2018 | 14,225 | | 2017 | 14,074 | | 2016 | 14,148 | | 2015 | 14,440 | | 2014 | 14,688 | | 2013 | 14,796 | | 2012 | 14,934 | | 2011 | 15,081 | | 2010 | 15,114 | | 2009 | 15,006 | | 2008 | 14,874 | | 2007 | 14,614 | | 2006 | 14,333 | | 2005 | 14,129 | | 2004 | 14,056 | | 2003 | 14,152 | | 2002 | 14,391 | | 2001 | 14,646 | | 2000 | 14,773 | | 1999 | 14,661 | | 1998 | 14,430 | | 1997 | 13,784 | | 1996 | 12,491 | | 1995 | 11,107 | | 1994 | 9,892 | | 1993 | 8,843 | | 1992 | 8,270 | | 1991 | 8,274 | | 1990 | 8,302 | | 1989 | 8,394 | | 1988 | 8,353 | | 1987 | 8,269 | | 1986 | 8,203 | | 1985 | 8,018 | | 1984 | 7,810 | | 1983 | 7,755 | | 1982 | 7,595 | | 1981 | 7,403 | | 1980 | 7,381 | | 1979 | 7,412 | | 1978 | 7,488 | | 1977 | 7,555 | | 1976 | 7,620 | | 1975 | 7,608 | | 1974 | 7,504 | | 1973 | 7,382 | | 1972 | 7,203 | | 1971 | 6,983 | | 1970 | 6,738 | | 1969 | 6,549 | | 1968 | 6,461 | | 1967 | 6,448 | | 1966 | 6,516 | | 1965 | 6,659 | | 1964 | 6,836 | | 1963 | 7,017 | | 1962 | 7,200 | | 1961 | 7,359 | | 1960 | 7,478 |
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