| Year | Value | | 2022 | 19,852 | | 2021 | 19,203 | | 2020 | 18,594 | | 2019 | 17,993 | | 2018 | 17,414 | | 2017 | 16,844 | | 2016 | 16,283 | | 2015 | 15,741 | | 2014 | 15,216 | | 2013 | 14,715 | | 2012 | 14,243 | | 2011 | 13,785 | | 2010 | 13,342 | | 2009 | 12,952 | | 2008 | 12,624 | | 2007 | 12,336 | | 2006 | 12,065 | | 2005 | 11,790 | | 2004 | 11,494 | | 2003 | 11,178 | | 2002 | 10,864 | | 2001 | 10,544 | | 2000 | 10,217 | | 1999 | 9,907 | | 1998 | 9,627 | | 1997 | 9,397 | | 1996 | 9,233 | | 1995 | 9,138 | | 1994 | 9,086 | | 1993 | 9,030 | | 1992 | 8,928 | | 1991 | 8,796 | | 1990 | 8,672 | | 1989 | 8,570 | | 1988 | 8,499 | | 1987 | 8,443 | | 1986 | 8,354 | | 1985 | 8,185 | | 1984 | 7,918 | | 1983 | 7,554 | | 1982 | 7,187 | | 1981 | 6,967 | | 1980 | 6,921 | | 1979 | 6,979 | | 1978 | 7,057 | | 1977 | 7,046 | | 1976 | 6,843 | | 1975 | 6,404 | | 1974 | 5,823 | | 1973 | 5,245 | | 1972 | 4,725 | | 1971 | 4,271 | | 1970 | 3,950 | | 1969 | 3,869 | | 1968 | 4,050 | | 1967 | 4,406 | | 1966 | 4,765 | | 1965 | 4,896 | | 1964 | 4,666 | | 1963 | 4,096 | | 1962 | 3,315 | | 1961 | 2,567 | | 1960 | 2,273 |
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