| Year | Value | | 2022 | 28,170 | | 2021 | 27,970 | | 2020 | 27,692 | | 2019 | 27,432 | | 2018 | 27,278 | | 2017 | 27,153 | | 2016 | 27,008 | | 2015 | 27,001 | | 2014 | 27,277 | | 2013 | 27,780 | | 2012 | 28,479 | | 2011 | 28,913 | | 2010 | 28,444 | | 2009 | 27,257 | | 2008 | 25,952 | | 2007 | 24,788 | | 2006 | 23,927 | | 2005 | 23,212 | | 2004 | 22,388 | | 2003 | 21,128 | | 2002 | 19,365 | | 2001 | 17,603 | | 2000 | 16,005 | | 1999 | 14,545 | | 1998 | 13,265 | | 1997 | 12,107 | | 1996 | 10,994 | | 1995 | 9,907 | | 1994 | 8,767 | | 1993 | 7,610 | | 1992 | 6,624 | | 1991 | 5,833 | | 1990 | 5,180 | | 1989 | 4,718 | | 1988 | 4,504 | | 1987 | 4,463 | | 1986 | 4,489 | | 1985 | 4,553 | | 1984 | 4,639 | | 1983 | 4,729 | | 1982 | 4,833 | | 1981 | 4,991 | | 1980 | 5,274 | | 1979 | 5,627 | | 1978 | 5,931 | | 1977 | 6,160 | | 1976 | 6,299 | | 1975 | 6,338 | | 1974 | 6,291 | | 1973 | 6,184 | | 1972 | 6,035 | | 1971 | 5,846 | | 1970 | 5,613 | | 1969 | 5,360 | | 1968 | 5,142 | | 1967 | 4,939 | | 1966 | 4,774 | | 1965 | 4,644 | | 1964 | 4,604 | | 1963 | 4,627 | | 1962 | 4,663 | | 1961 | 4,679 | | 1960 | 4,795 |
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