| Year | Value | | 2022 | 19,985 | | 2021 | 19,812 | | 2020 | 19,633 | | 2019 | 19,389 | | 2018 | 19,064 | | 2017 | 18,761 | | 2016 | 18,432 | | 2015 | 18,031 | | 2014 | 17,545 | | 2013 | 16,987 | | 2012 | 16,391 | | 2011 | 15,779 | | 2010 | 15,151 | | 2009 | 14,628 | | 2008 | 14,226 | | 2007 | 13,824 | | 2006 | 13,407 | | 2005 | 12,973 | | 2004 | 12,529 | | 2003 | 12,108 | | 2002 | 11,777 | | 2001 | 11,509 | | 2000 | 11,264 | | 1999 | 11,047 | | 1998 | 10,809 | | 1997 | 10,493 | | 1996 | 10,127 | | 1995 | 9,740 | | 1994 | 9,325 | | 1993 | 8,932 | | 1992 | 8,603 | | 1991 | 8,426 | | 1990 | 8,390 | | 1989 | 8,415 | | 1988 | 8,461 | | 1987 | 8,478 | | 1986 | 8,456 | | 1985 | 8,372 | | 1984 | 8,200 | | 1983 | 7,918 | | 1982 | 7,539 | | 1981 | 7,104 | | 1980 | 6,672 | | 1979 | 6,301 | | 1978 | 6,007 | | 1977 | 5,766 | | 1976 | 5,536 | | 1975 | 5,296 | | 1974 | 5,094 | | 1973 | 4,923 | | 1972 | 4,716 | | 1971 | 4,492 | | 1970 | 4,255 | | 1969 | 4,019 | | 1968 | 3,824 | | 1967 | 3,682 | | 1966 | 3,583 | | 1965 | 3,516 | | 1964 | 3,478 | | 1963 | 3,457 | | 1962 | 3,431 | | 1961 | 3,394 | | 1960 | 3,342 |
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