| Year | Value | | 2022 | 14,078 | | 2021 | 13,604 | | 2020 | 13,524 | | 2019 | 13,491 | | 2018 | 13,370 | | 2017 | 13,387 | | 2016 | 13,592 | | 2015 | 13,953 | | 2014 | 14,301 | | 2013 | 14,586 | | 2012 | 14,872 | | 2011 | 15,087 | | 2010 | 15,140 | | 2009 | 14,982 | | 2008 | 14,715 | | 2007 | 14,391 | | 2006 | 14,133 | | 2005 | 14,035 | | 2004 | 14,078 | | 2003 | 14,194 | | 2002 | 14,400 | | 2001 | 14,722 | | 2000 | 14,953 | | 1999 | 14,954 | | 1998 | 14,834 | | 1997 | 14,264 | | 1996 | 12,997 | | 1995 | 11,621 | | 1994 | 10,469 | | 1993 | 9,530 | | 1992 | 9,060 | | 1991 | 9,140 | | 1990 | 9,225 | | 1989 | 9,379 | | 1988 | 9,430 | | 1987 | 9,464 | | 1986 | 9,529 | | 1985 | 9,445 | | 1984 | 9,288 | | 1983 | 9,246 | | 1982 | 9,016 | | 1981 | 8,693 | | 1980 | 8,549 | | 1979 | 8,458 | | 1978 | 8,429 | | 1977 | 8,414 | | 1976 | 8,409 | | 1975 | 8,322 | | 1974 | 8,148 | | 1973 | 7,964 | | 1972 | 7,724 | | 1971 | 7,468 | | 1970 | 7,208 | | 1969 | 7,024 | | 1968 | 6,948 | | 1967 | 6,947 | | 1966 | 7,009 | | 1965 | 7,118 | | 1964 | 7,257 | | 1963 | 7,422 | | 1962 | 7,612 | | 1961 | 7,808 | | 1960 | 7,990 |
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