| Year | Value | | 2022 | 15,434 | | 2021 | 15,456 | | 2020 | 15,397 | | 2019 | 15,384 | | 2018 | 15,508 | | 2017 | 15,648 | | 2016 | 15,779 | | 2015 | 15,945 | | 2014 | 15,962 | | 2013 | 15,730 | | 2012 | 15,425 | | 2011 | 15,073 | | 2010 | 14,646 | | 2009 | 14,393 | | 2008 | 14,347 | | 2007 | 14,293 | | 2006 | 14,186 | | 2005 | 14,020 | | 2004 | 13,765 | | 2003 | 13,383 | | 2002 | 12,895 | | 2001 | 12,357 | | 2000 | 11,798 | | 1999 | 11,220 | | 1998 | 10,625 | | 1997 | 9,993 | | 1996 | 9,356 | | 1995 | 8,770 | | 1994 | 8,243 | | 1993 | 7,816 | | 1992 | 7,475 | | 1991 | 7,171 | | 1990 | 6,878 | | 1989 | 6,641 | | 1988 | 6,510 | | 1987 | 6,476 | | 1986 | 6,514 | | 1985 | 6,558 | | 1984 | 6,536 | | 1983 | 6,428 | | 1982 | 6,274 | | 1981 | 6,092 | | 1980 | 5,870 | | 1979 | 5,628 | | 1978 | 5,408 | | 1977 | 5,207 | | 1976 | 5,024 | | 1975 | 4,860 | | 1974 | 4,702 | | 1973 | 4,549 | | 1972 | 4,391 | | 1971 | 4,215 | | 1970 | 4,022 | | 1969 | 3,836 | | 1968 | 3,674 | | 1967 | 3,544 | | 1966 | 3,444 | | 1965 | 3,362 | | 1964 | 3,283 | | 1963 | 3,211 | | 1962 | 3,160 | | 1961 | 3,119 | | 1960 | 3,082 |
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