| Year | Value | | 2022 | 29,394 | | 2021 | 28,786 | | 2020 | 28,129 | | 2019 | 27,326 | | 2018 | 26,754 | | 2017 | 26,542 | | 2016 | 26,523 | | 2015 | 26,605 | | 2014 | 26,800 | | 2013 | 26,882 | | 2012 | 26,713 | | 2011 | 26,196 | | 2010 | 25,691 | | 2009 | 25,629 | | 2008 | 25,960 | | 2007 | 26,604 | | 2006 | 26,999 | | 2005 | 26,719 | | 2004 | 25,964 | | 2003 | 24,973 | | 2002 | 23,931 | | 2001 | 23,182 | | 2000 | 22,594 | | 1999 | 21,805 | | 1998 | 20,554 | | 1997 | 18,831 | | 1996 | 17,096 | | 1995 | 15,505 | | 1994 | 14,086 | | 1993 | 12,863 | | 1992 | 11,747 | | 1991 | 10,609 | | 1990 | 9,441 | | 1989 | 8,260 | | 1988 | 7,123 | | 1987 | 6,192 | | 1986 | 5,479 | | 1985 | 4,937 | | 1984 | 4,577 | | 1983 | 4,399 | | 1982 | 4,339 | | 1981 | 4,354 | | 1980 | 4,488 | | 1979 | 4,736 | | 1978 | 5,029 | | 1977 | 5,344 | | 1976 | 5,661 | | 1975 | 5,974 | | 1974 | 6,261 | | 1973 | 6,494 | | 1972 | 6,658 | | 1971 | 6,746 | | 1970 | 6,671 | | 1969 | 6,459 | | 1968 | 6,223 | | 1967 | 6,008 | | 1966 | 5,832 | | 1965 | 5,707 | | 1964 | 5,565 | | 1963 | 5,421 | | 1962 | 5,276 | | 1961 | 5,152 | | 1960 | 5,165 |
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