| Year | Value | | 2022 | 22,141 | | 2021 | 21,062 | | 2020 | 20,531 | | 2019 | 19,633 | | 2018 | 18,391 | | 2017 | 17,244 | | 2016 | 16,294 | | 2015 | 15,453 | | 2014 | 14,563 | | 2013 | 13,828 | | 2012 | 13,338 | | 2011 | 12,987 | | 2010 | 12,717 | | 2009 | 12,632 | | 2008 | 12,719 | | 2007 | 12,972 | | 2006 | 13,362 | | 2005 | 13,931 | | 2004 | 14,449 | | 2003 | 14,737 | | 2002 | 14,928 | | 2001 | 15,040 | | 2000 | 15,008 | | 1999 | 14,895 | | 1998 | 14,839 | | 1997 | 14,649 | | 1996 | 14,343 | | 1995 | 14,114 | | 1994 | 14,073 | | 1993 | 14,166 | | 1992 | 14,386 | | 1991 | 14,659 | | 1990 | 14,552 | | 1989 | 14,393 | | 1988 | 13,983 | | 1987 | 13,233 | | 1986 | 12,105 | | 1985 | 10,886 | | 1984 | 9,881 | | 1983 | 9,238 | | 1982 | 8,725 | | 1981 | 8,458 | | 1980 | 8,467 | | 1979 | 8,482 | | 1978 | 8,461 | | 1977 | 8,404 | | 1976 | 8,366 | | 1975 | 8,239 | | 1974 | 8,049 | | 1973 | 7,915 | | 1972 | 7,803 | | 1971 | 7,760 | | 1970 | 7,798 | | 1969 | 7,934 | | 1968 | 8,131 | | 1967 | 8,301 | | 1966 | 8,402 | | 1965 | 8,417 | | 1964 | 8,345 | | 1963 | 8,206 | | 1962 | 8,027 | | 1961 | 7,821 | | 1960 | 7,626 |
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