| Year | Value | | 2022 | 35,608 | | 2021 | 35,079 | | 2020 | 34,099 | | 2019 | 32,686 | | 2018 | 31,156 | | 2017 | 29,709 | | 2016 | 28,462 | | 2015 | 27,384 | | 2014 | 26,520 | | 2013 | 26,060 | | 2012 | 26,033 | | 2011 | 26,312 | | 2010 | 26,806 | | 2009 | 27,493 | | 2008 | 28,297 | | 2007 | 29,016 | | 2006 | 29,454 | | 2005 | 29,587 | | 2004 | 29,448 | | 2003 | 29,022 | | 2002 | 28,389 | | 2001 | 27,752 | | 2000 | 27,181 | | 1999 | 26,641 | | 1998 | 26,269 | | 1997 | 26,120 | | 1996 | 26,149 | | 1995 | 26,102 | | 1994 | 26,812 | | 1993 | 28,204 | | 1992 | 29,020 | | 1991 | 29,258 | | 1990 | 29,255 | | 1989 | 27,621 | | 1988 | 24,553 | | 1987 | 22,300 | | 1986 | 20,895 | | 1985 | 19,757 | | 1984 | 18,698 | | 1983 | 17,749 | | 1982 | 16,902 | | 1981 | 16,175 | | 1980 | 15,592 | | 1979 | 15,219 | | 1978 | 14,964 | | 1977 | 14,665 | | 1976 | 14,341 | | 1975 | 14,027 | | 1974 | 13,731 | | 1973 | 13,463 | | 1972 | 13,212 | | 1971 | 12,943 | | 1970 | 12,635 | | 1969 | 12,287 | | 1968 | 11,902 | | 1967 | 11,484 | | 1966 | 11,077 | | 1965 | 10,704 | | 1964 | 10,362 | | 1963 | 10,053 | | 1962 | 9,770 | | 1961 | 9,485 | | 1960 | 9,178 |
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