| Year | Value | | 2022 | 27,490 | | 2021 | 27,637 | | 2020 | 27,926 | | 2019 | 28,260 | | 2018 | 28,629 | | 2017 | 28,983 | | 2016 | 29,122 | | 2015 | 28,694 | | 2014 | 27,664 | | 2013 | 26,445 | | 2012 | 25,395 | | 2011 | 24,605 | | 2010 | 23,873 | | 2009 | 23,073 | | 2008 | 21,901 | | 2007 | 20,140 | | 2006 | 18,283 | | 2005 | 16,647 | | 2004 | 15,130 | | 2003 | 13,739 | | 2002 | 12,488 | | 2001 | 11,331 | | 2000 | 10,233 | | 1999 | 9,070 | | 1998 | 7,906 | | 1997 | 6,900 | | 1996 | 6,059 | | 1995 | 5,363 | | 1994 | 4,863 | | 1993 | 4,619 | | 1992 | 4,578 | | 1991 | 4,628 | | 1990 | 4,739 | | 1989 | 4,877 | | 1988 | 4,982 | | 1987 | 5,075 | | 1986 | 5,198 | | 1985 | 5,351 | | 1984 | 5,506 | | 1983 | 5,657 | | 1982 | 5,787 | | 1981 | 5,870 | | 1980 | 5,897 | | 1979 | 5,862 | | 1978 | 5,766 | | 1977 | 5,638 | | 1976 | 5,501 | | 1975 | 5,355 | | 1974 | 5,186 | | 1973 | 4,978 | | 1972 | 4,722 | | 1971 | 4,432 | | 1970 | 4,208 | | 1969 | 4,106 | | 1968 | 4,063 | | 1967 | 4,070 | | 1966 | 4,093 | | 1965 | 4,136 | | 1964 | 4,136 | | 1963 | 4,056 | | 1962 | 3,962 | | 1961 | 3,910 | | 1960 | 3,889 |
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