| Year | Value | | 2022 | 22,043 | | 2021 | 21,898 | | 2020 | 21,741 | | 2019 | 21,569 | | 2018 | 21,372 | | 2017 | 21,141 | | 2016 | 20,868 | | 2015 | 20,524 | | 2014 | 20,095 | | 2013 | 19,571 | | 2012 | 18,941 | | 2011 | 18,219 | | 2010 | 17,456 | | 2009 | 16,850 | | 2008 | 16,421 | | 2007 | 16,052 | | 2006 | 15,754 | | 2005 | 15,497 | | 2004 | 15,239 | | 2003 | 14,995 | | 2002 | 14,784 | | 2001 | 14,598 | | 2000 | 14,479 | | 1999 | 14,384 | | 1998 | 14,260 | | 1997 | 14,135 | | 1996 | 14,002 | | 1995 | 13,845 | | 1994 | 13,657 | | 1993 | 13,443 | | 1992 | 13,204 | | 1991 | 12,944 | | 1990 | 12,661 | | 1989 | 12,382 | | 1988 | 12,108 | | 1987 | 11,816 | | 1986 | 11,508 | | 1985 | 11,191 | | 1984 | 10,879 | | 1983 | 10,514 | | 1982 | 10,092 | | 1981 | 9,704 | | 1980 | 9,381 | | 1979 | 9,370 | | 1978 | 9,481 | | 1977 | 9,344 | | 1976 | 9,116 | | 1975 | 8,885 | | 1974 | 8,652 | | 1973 | 8,417 | | 1972 | 8,182 | | 1971 | 7,944 | | 1970 | 7,704 | | 1969 | 7,471 | | 1968 | 7,245 | | 1967 | 7,031 | | 1966 | 6,828 | | 1965 | 6,632 | | 1964 | 6,444 | | 1963 | 6,257 | | 1962 | 6,072 | | 1961 | 5,892 | | 1960 | 5,714 |
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