| Year | Value | | 2018 | 7,797 | | 2017 | 7,472 | | 2016 | 7,150 | | 2015 | 6,830 | | 2014 | 6,468 | | 2013 | 6,101 | | 2012 | 5,748 | | 2011 | 5,441 | | 2010 | 5,203 | | 2009 | 5,007 | | 2008 | 4,890 | | 2007 | 4,834 | | 2006 | 4,800 | | 2005 | 4,761 | | 2004 | 4,692 | | 2003 | 4,620 | | 2002 | 4,546 | | 2001 | 4,472 | | 2000 | 4,400 | | 1999 | 4,292 | | 1998 | 4,179 | | 1997 | 4,063 | | 1996 | 3,954 | | 1995 | 3,858 | | 1994 | 3,751 | | 1993 | 3,659 | | 1992 | 3,581 | | 1991 | 3,510 | | 1990 | 3,447 | | 1989 | 3,368 | | 1988 | 3,295 | | 1987 | 3,227 | | 1986 | 3,170 | | 1985 | 3,124 | | 1984 | 3,067 | | 1983 | 3,021 | | 1982 | 2,980 | | 1981 | 2,937 | | 1980 | 2,888 | | 1979 | 2,809 | | 1978 | 2,724 | | 1977 | 2,639 | | 1976 | 2,563 | | 1975 | 2,501 | | 1974 | 2,440 | | 1973 | 2,390 | | 1972 | 2,349 | | 1971 | 2,308 | | 1970 | 2,263 | | 1969 | 2,197 | | 1968 | 2,122 | | 1967 | 2,043 | | 1966 | 1,971 | | 1965 | 1,912 | | 1964 | 1,856 | | 1963 | 1,815 | | 1962 | 1,783 | | 1961 | 1,759 | | 1960 | 1,737 |
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