| Year | Value | | 2022 | 21,041 | | 2021 | 21,097 | | 2020 | 20,995 | | 2019 | 20,901 | | 2018 | 20,754 | | 2017 | 20,487 | | 2016 | 20,203 | | 2015 | 19,869 | | 2014 | 19,358 | | 2013 | 18,692 | | 2012 | 17,936 | | 2011 | 17,093 | | 2010 | 16,173 | | 2009 | 15,444 | | 2008 | 14,989 | | 2007 | 14,643 | | 2006 | 14,419 | | 2005 | 14,278 | | 2004 | 13,939 | | 2003 | 13,411 | | 2002 | 12,954 | | 2001 | 12,576 | | 2000 | 12,272 | | 1999 | 12,046 | | 1998 | 11,819 | | 1997 | 11,521 | | 1996 | 11,183 | | 1995 | 10,897 | | 1994 | 10,653 | | 1993 | 10,382 | | 1992 | 10,084 | | 1991 | 9,801 | | 1990 | 9,487 | | 1989 | 9,126 | | 1988 | 8,785 | | 1987 | 8,458 | | 1986 | 8,172 | | 1985 | 7,888 | | 1984 | 7,574 | | 1983 | 7,298 | | 1982 | 7,080 | | 1981 | 6,912 | | 1980 | 6,785 | | 1979 | 6,679 | | 1978 | 6,578 | | 1977 | 6,490 | | 1976 | 6,386 | | 1975 | 6,246 | | 1974 | 6,088 | | 1973 | 5,906 | | 1972 | 5,699 | | 1971 | 5,477 | | 1970 | 5,250 | | 1969 | 5,025 | | 1968 | 4,814 | | 1967 | 4,621 | | 1966 | 4,415 | | 1965 | 4,205 | | 1964 | 4,031 | | 1963 | 3,886 | | 1962 | 3,753 | | 1961 | 3,628 | | 1960 | 3,521 |
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