| Year | Value | | 2022 | 28,327 | | 2021 | 27,425 | | 2020 | 26,448 | | 2019 | 25,550 | | 2018 | 24,767 | | 2017 | 24,070 | | 2016 | 23,444 | | 2015 | 22,870 | | 2014 | 22,339 | | 2013 | 21,853 | | 2012 | 21,420 | | 2011 | 21,038 | | 2010 | 20,701 | | 2009 | 20,401 | | 2008 | 20,117 | | 2007 | 19,825 | | 2006 | 19,502 | | 2005 | 19,139 | | 2004 | 18,773 | | 2003 | 18,441 | | 2002 | 18,151 | | 2001 | 17,930 | | 2000 | 17,784 | | 1999 | 17,561 | | 1998 | 17,176 | | 1997 | 16,696 | | 1996 | 16,125 | | 1995 | 15,457 | | 1994 | 14,768 | | 1993 | 14,123 | | 1992 | 13,490 | | 1991 | 12,857 | | 1990 | 12,224 | | 1989 | 11,588 | | 1988 | 10,983 | | 1987 | 10,412 | | 1986 | 9,835 | | 1985 | 9,268 | | 1984 | 8,760 | | 1983 | 8,307 | | 1982 | 7,920 | | 1981 | 7,636 | | 1980 | 7,430 | | 1979 | 7,278 | | 1978 | 7,156 | | 1977 | 7,047 | | 1976 | 6,951 | | 1975 | 6,871 | | 1974 | 6,778 | | 1973 | 6,651 | | 1972 | 6,511 | | 1971 | 6,365 | | 1970 | 6,219 | | 1969 | 6,086 | | 1968 | 5,972 | | 1967 | 5,871 | | 1966 | 5,777 | | 1965 | 5,682 | | 1964 | 5,574 | | 1963 | 5,453 | | 1962 | 5,325 | | 1961 | 5,195 | | 1960 | 5,067 |
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