| Year | Value | | 2022 | 25,197 | | 2021 | 24,778 | | 2020 | 24,280 | | 2019 | 23,660 | | 2018 | 22,960 | | 2017 | 22,212 | | 2016 | 21,463 | | 2015 | 20,759 | | 2014 | 20,103 | | 2013 | 19,483 | | 2012 | 18,899 | | 2011 | 18,333 | | 2010 | 17,692 | | 2009 | 17,024 | | 2008 | 16,452 | | 2007 | 15,987 | | 2006 | 15,612 | | 2005 | 15,299 | | 2004 | 15,026 | | 2003 | 14,766 | | 2002 | 14,510 | | 2001 | 14,200 | | 2000 | 13,823 | | 1999 | 13,435 | | 1998 | 13,056 | | 1997 | 12,685 | | 1996 | 12,325 | | 1995 | 11,987 | | 1994 | 11,677 | | 1993 | 11,417 | | 1992 | 11,219 | | 1991 | 11,092 | | 1990 | 11,026 | | 1989 | 10,986 | | 1988 | 10,951 | | 1987 | 10,925 | | 1986 | 10,914 | | 1985 | 10,919 | | 1984 | 10,933 | | 1983 | 10,926 | | 1982 | 10,873 | | 1981 | 10,754 | | 1980 | 10,532 | | 1979 | 10,226 | | 1978 | 9,927 | | 1977 | 9,747 | | 1976 | 9,743 | | 1975 | 9,805 | | 1974 | 9,810 | | 1973 | 9,697 | | 1972 | 9,369 | | 1971 | 8,915 | | 1970 | 8,406 | | 1969 | 7,741 | | 1968 | 6,911 | | 1967 | 6,005 | | 1966 | 5,201 | | 1965 | 4,739 | | 1964 | 4,752 | | 1963 | 5,162 | | 1962 | 5,756 | | 1961 | 6,252 | | 1960 | 6,317 |
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