| Year | Value | | 2022 | 17,852 | | 2021 | 18,067 | | 2020 | 18,207 | | 2019 | 18,176 | | 2018 | 18,017 | | 2017 | 17,802 | | 2016 | 17,619 | | 2015 | 17,553 | | 2014 | 17,567 | | 2013 | 17,547 | | 2012 | 17,419 | | 2011 | 17,142 | | 2010 | 16,709 | | 2009 | 16,162 | | 2008 | 15,577 | | 2007 | 15,023 | | 2006 | 14,514 | | 2005 | 14,059 | | 2004 | 13,662 | | 2003 | 13,179 | | 2002 | 12,537 | | 2001 | 11,795 | | 2000 | 10,978 | | 1999 | 10,146 | | 1998 | 9,368 | | 1997 | 8,687 | | 1996 | 8,123 | | 1995 | 7,649 | | 1994 | 7,349 | | 1993 | 7,252 | | 1992 | 7,234 | | 1991 | 7,242 | | 1990 | 7,279 | | 1989 | 7,308 | | 1988 | 7,312 | | 1987 | 7,336 | | 1986 | 7,376 | | 1985 | 7,398 | | 1984 | 7,424 | | 1983 | 7,455 | | 1982 | 7,480 | | 1981 | 7,486 | | 1980 | 7,468 | | 1979 | 7,407 | | 1978 | 7,291 | | 1977 | 7,145 | | 1976 | 6,997 | | 1975 | 6,870 | | 1974 | 6,773 | | 1973 | 6,694 | | 1972 | 6,612 | | 1971 | 6,429 | | 1970 | 6,129 | | 1969 | 5,798 | | 1968 | 5,487 | | 1967 | 5,244 | | 1966 | 5,065 | | 1965 | 4,944 | | 1964 | 4,880 | | 1963 | 4,815 | | 1962 | 4,702 | | 1961 | 4,611 | | 1960 | 4,576 |
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