| Year | Value | | 2022 | 6,525 | | 2021 | 6,508 | | 2020 | 6,408 | | 2019 | 6,250 | | 2018 | 6,003 | | 2017 | 5,768 | | 2016 | 5,604 | | 2015 | 5,436 | | 2014 | 5,324 | | 2013 | 5,251 | | 2012 | 5,209 | | 2011 | 5,275 | | 2010 | 5,346 | | 2009 | 5,323 | | 2008 | 5,221 | | 2007 | 5,083 | | 2006 | 4,952 | | 2005 | 4,836 | | 2004 | 4,756 | | 2003 | 4,764 | | 2002 | 4,855 | | 2001 | 4,998 | | 2000 | 5,182 | | 1999 | 5,394 | | 1998 | 5,621 | | 1997 | 5,849 | | 1996 | 6,034 | | 1995 | 6,208 | | 1994 | 6,412 | | 1993 | 6,560 | | 1992 | 6,609 | | 1991 | 6,577 | | 1990 | 6,435 | | 1989 | 6,234 | | 1988 | 6,048 | | 1987 | 5,878 | | 1986 | 5,712 | | 1985 | 5,516 | | 1984 | 5,342 | | 1983 | 5,224 | | 1982 | 5,097 | | 1981 | 5,009 | | 1980 | 5,052 | | 1979 | 5,226 | | 1978 | 5,495 | | 1977 | 5,783 | | 1976 | 5,906 | | 1975 | 5,735 | | 1974 | 5,377 | | 1973 | 4,985 | | 1972 | 4,628 | | 1971 | 4,358 | | 1970 | 4,169 | | 1969 | 4,062 | | 1968 | 4,038 | | 1967 | 4,074 | | 1966 | 4,142 | | 1965 | 4,210 | | 1964 | 4,237 | | 1963 | 4,212 | | 1962 | 4,153 | | 1961 | 4,029 | | 1960 | 3,787 |
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