| Year | Value | | 2022 | 15,154 | | 2021 | 15,167 | | 2020 | 15,657 | | 2019 | 15,872 | | 2018 | 15,656 | | 2017 | 15,503 | | 2016 | 15,424 | | 2015 | 15,251 | | 2014 | 14,969 | | 2013 | 14,782 | | 2012 | 14,532 | | 2011 | 14,274 | | 2010 | 14,169 | | 2009 | 14,213 | | 2008 | 14,354 | | 2007 | 14,636 | | 2006 | 14,959 | | 2005 | 15,103 | | 2004 | 14,959 | | 2003 | 14,681 | | 2002 | 13,931 | | 2001 | 12,513 | | 2000 | 11,060 | | 1999 | 9,856 | | 1998 | 8,819 | | 1997 | 8,264 | | 1996 | 8,347 | | 1995 | 8,610 | | 1994 | 8,732 | | 1993 | 8,631 | | 1992 | 8,453 | | 1991 | 8,293 | | 1990 | 7,953 | | 1989 | 7,759 | | 1988 | 7,620 | | 1987 | 7,488 | | 1986 | 7,377 | | 1985 | 7,255 | | 1984 | 7,206 | | 1983 | 7,334 | | 1982 | 7,366 | | 1981 | 7,301 | | 1980 | 7,287 | | 1979 | 7,181 | | 1978 | 6,998 | | 1977 | 6,755 | | 1976 | 6,522 | | 1975 | 6,272 | | 1974 | 6,039 | | 1973 | 5,928 | | 1972 | 5,902 | | 1971 | 5,960 | | 1970 | 6,082 | | 1969 | 6,278 | | 1968 | 6,524 | | 1967 | 6,751 | | 1966 | 6,935 | | 1965 | 7,060 | | 1964 | 7,082 | | 1963 | 7,001 | | 1962 | 6,871 | | 1961 | 6,705 | | 1960 | 6,530 |
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