| Year | Value | | 2022 | 22,997 | | 2021 | 22,765 | | 2020 | 22,573 | | 2019 | 22,371 | | 2018 | 22,110 | | 2017 | 21,737 | | 2016 | 21,159 | | 2015 | 20,645 | | 2014 | 19,994 | | 2013 | 19,272 | | 2012 | 18,600 | | 2011 | 18,021 | | 2010 | 17,422 | | 2009 | 16,911 | | 2008 | 16,501 | | 2007 | 16,035 | | 2006 | 15,476 | | 2005 | 14,936 | | 2004 | 14,471 | | 2003 | 14,037 | | 2002 | 13,662 | | 2001 | 13,389 | | 2000 | 13,194 | | 1999 | 12,846 | | 1998 | 12,458 | | 1997 | 12,132 | | 1996 | 11,736 | | 1995 | 11,515 | | 1994 | 11,560 | | 1993 | 11,568 | | 1992 | 11,477 | | 1991 | 11,437 | | 1990 | 11,420 | | 1989 | 11,297 | | 1988 | 11,147 | | 1987 | 11,116 | | 1986 | 11,249 | | 1985 | 11,524 | | 1984 | 11,811 | | 1983 | 12,026 | | 1982 | 12,199 | | 1981 | 12,241 | | 1980 | 12,111 | | 1979 | 11,902 | | 1978 | 11,761 | | 1977 | 11,695 | | 1976 | 11,631 | | 1975 | 11,621 | | 1974 | 11,407 | | 1973 | 10,725 | | 1972 | 9,997 | | 1971 | 9,424 | | 1970 | 8,938 | | 1969 | 8,917 | | 1968 | 9,440 | | 1967 | 10,195 | | 1966 | 10,896 | | 1965 | 11,323 | | 1964 | 11,447 | | 1963 | 11,539 | | 1962 | 11,626 | | 1961 | 11,625 | | 1960 | 11,647 |
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