| Year | Value | | 2022 | 24,076 | | 2021 | 23,425 | | 2020 | 22,943 | | 2019 | 22,525 | | 2018 | 22,228 | | 2017 | 22,051 | | 2016 | 21,986 | | 2015 | 22,052 | | 2014 | 21,989 | | 2013 | 21,712 | | 2012 | 21,383 | | 2011 | 20,975 | | 2010 | 20,502 | | 2009 | 20,009 | | 2008 | 19,518 | | 2007 | 19,044 | | 2006 | 18,641 | | 2005 | 18,319 | | 2004 | 17,922 | | 2003 | 17,368 | | 2002 | 16,726 | | 2001 | 16,014 | | 2000 | 15,255 | | 1999 | 14,475 | | 1998 | 13,693 | | 1997 | 12,915 | | 1996 | 12,373 | | 1995 | 12,060 | | 1994 | 11,746 | | 1993 | 11,431 | | 1992 | 11,110 | | 1991 | 10,779 | | 1990 | 10,438 | | 1989 | 10,087 | | 1988 | 9,721 | | 1987 | 9,349 | | 1986 | 8,992 | | 1985 | 8,669 | | 1984 | 8,381 | | 1983 | 8,130 | | 1982 | 7,910 | | 1981 | 7,696 | | 1980 | 7,476 | | 1979 | 7,259 | | 1978 | 7,043 | | 1977 | 6,819 | | 1976 | 6,596 | | 1975 | 6,381 | | 1974 | 6,170 | | 1973 | 5,973 | | 1972 | 5,796 | | 1971 | 5,619 | | 1970 | 5,431 | | 1969 | 5,237 | | 1968 | 5,033 | | 1967 | 4,826 | | 1966 | 4,626 | | 1965 | 4,442 | | 1964 | 4,269 | | 1963 | 4,106 | | 1962 | 3,953 | | 1961 | 3,820 | | 1960 | 3,715 |
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