| Year | Value | | 2022 | 18,431 | | 2021 | 18,453 | | 2020 | 18,276 | | 2019 | 17,918 | | 2018 | 17,400 | | 2017 | 16,852 | | 2016 | 16,314 | | 2015 | 15,793 | | 2014 | 15,311 | | 2013 | 14,891 | | 2012 | 14,541 | | 2011 | 14,272 | | 2010 | 14,083 | | 2009 | 13,944 | | 2008 | 13,742 | | 2007 | 13,496 | | 2006 | 13,231 | | 2005 | 12,869 | | 2004 | 12,432 | | 2003 | 12,021 | | 2002 | 11,608 | | 2001 | 11,125 | | 2000 | 10,622 | | 1999 | 10,113 | | 1998 | 9,613 | | 1997 | 9,154 | | 1996 | 8,796 | | 1995 | 8,510 | | 1994 | 8,389 | | 1993 | 8,280 | | 1992 | 7,971 | | 1991 | 7,630 | | 1990 | 7,318 | | 1989 | 7,091 | | 1988 | 6,852 | | 1987 | 6,601 | | 1986 | 6,435 | | 1985 | 6,292 | | 1984 | 6,215 | | 1983 | 6,209 | | 1982 | 6,208 | | 1981 | 6,255 | | 1980 | 6,290 | | 1979 | 6,256 | | 1978 | 6,213 | | 1977 | 6,169 | | 1976 | 6,095 | | 1975 | 5,991 | | 1974 | 5,885 | | 1973 | 5,776 | | 1972 | 5,667 | | 1971 | 5,556 | | 1970 | 5,442 | | 1969 | 5,323 | | 1968 | 5,201 | | 1967 | 5,081 | | 1966 | 4,963 | | 1965 | 4,850 | | 1964 | 4,748 | | 1963 | 4,657 | | 1962 | 4,566 | | 1961 | 4,469 | | 1960 | 4,364 |
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