| Year | Value | | 2022 | 23,501 | | 2021 | 23,231 | | 2020 | 22,920 | | 2019 | 22,316 | | 2018 | 21,474 | | 2017 | 20,596 | | 2016 | 19,753 | | 2015 | 18,983 | | 2014 | 18,276 | | 2013 | 17,631 | | 2012 | 17,052 | | 2011 | 16,534 | | 2010 | 16,330 | | 2009 | 16,184 | | 2008 | 15,857 | | 2007 | 15,591 | | 2006 | 15,354 | | 2005 | 15,129 | | 2004 | 14,923 | | 2003 | 14,725 | | 2002 | 14,522 | | 2001 | 14,330 | | 2000 | 14,138 | | 1999 | 13,943 | | 1998 | 13,751 | | 1997 | 13,564 | | 1996 | 13,368 | | 1995 | 13,156 | | 1994 | 12,930 | | 1993 | 12,693 | | 1992 | 12,448 | | 1991 | 12,200 | | 1990 | 11,948 | | 1989 | 11,693 | | 1988 | 11,431 | | 1987 | 11,162 | | 1986 | 10,877 | | 1985 | 10,563 | | 1984 | 10,214 | | 1983 | 9,832 | | 1982 | 9,425 | | 1981 | 9,008 | | 1980 | 8,599 | | 1979 | 8,201 | | 1978 | 7,807 | | 1977 | 7,427 | | 1976 | 7,079 | | 1975 | 6,773 | | 1974 | 6,513 | | 1973 | 6,321 | | 1972 | 6,187 | | 1971 | 6,068 | | 1970 | 5,942 | | 1969 | 5,819 | | 1968 | 5,698 | | 1967 | 5,571 | | 1966 | 5,469 | | 1965 | 5,413 | | 1964 | 5,399 | | 1963 | 5,435 | | 1962 | 5,511 | | 1961 | 5,598 | | 1960 | 5,684 |
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