| Year | Value | | 2022 | 22,977 | | 2021 | 23,068 | | 2020 | 23,138 | | 2019 | 23,239 | | 2018 | 23,415 | | 2017 | 23,647 | | 2016 | 23,741 | | 2015 | 23,705 | | 2014 | 23,658 | | 2013 | 23,506 | | 2012 | 23,226 | | 2011 | 22,925 | | 2010 | 22,568 | | 2009 | 22,034 | | 2008 | 21,347 | | 2007 | 20,524 | | 2006 | 19,562 | | 2005 | 18,498 | | 2004 | 17,617 | | 2003 | 16,978 | | 2002 | 16,402 | | 2001 | 15,942 | | 2000 | 15,601 | | 1999 | 15,092 | | 1998 | 14,434 | | 1997 | 13,862 | | 1996 | 13,426 | | 1995 | 13,185 | | 1994 | 13,082 | | 1993 | 12,999 | | 1992 | 12,889 | | 1991 | 12,786 | | 1990 | 12,644 | | 1989 | 12,442 | | 1988 | 12,229 | | 1987 | 11,993 | | 1986 | 11,615 | | 1985 | 11,141 | | 1984 | 10,715 | | 1983 | 10,319 | | 1982 | 9,949 | | 1981 | 9,590 | | 1980 | 9,236 | | 1979 | 8,893 | | 1978 | 8,575 | | 1977 | 8,289 | | 1976 | 8,082 | | 1975 | 7,952 | | 1974 | 7,855 | | 1973 | 7,784 | | 1972 | 7,722 | | 1971 | 7,651 | | 1970 | 7,579 | | 1969 | 7,496 | | 1968 | 7,384 | | 1967 | 7,233 | | 1966 | 7,013 | | 1965 | 6,743 | | 1964 | 6,464 | | 1963 | 6,177 | | 1962 | 5,896 | | 1961 | 5,626 | | 1960 | 5,363 |
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