| Year | Value | | 2018 | 8,379 | | 2017 | 8,033 | | 2016 | 7,683 | | 2015 | 7,331 | | 2014 | 6,921 | | 2013 | 6,497 | | 2012 | 6,083 | | 2011 | 5,730 | | 2010 | 5,474 | | 2009 | 5,278 | | 2008 | 5,191 | | 2007 | 5,177 | | 2006 | 5,184 | | 2005 | 5,172 | | 2004 | 5,112 | | 2003 | 5,032 | | 2002 | 4,936 | | 2001 | 4,847 | | 2000 | 4,775 | | 1999 | 4,678 | | 1998 | 4,586 | | 1997 | 4,502 | | 1996 | 4,420 | | 1995 | 4,344 | | 1994 | 4,246 | | 1993 | 4,154 | | 1992 | 4,067 | | 1991 | 3,989 | | 1990 | 3,919 | | 1989 | 3,837 | | 1988 | 3,760 | | 1987 | 3,693 | | 1986 | 3,638 | | 1985 | 3,592 | | 1984 | 3,533 | | 1983 | 3,484 | | 1982 | 3,441 | | 1981 | 3,398 | | 1980 | 3,345 | | 1979 | 3,257 | | 1978 | 3,163 | | 1977 | 3,069 | | 1976 | 2,982 | | 1975 | 2,910 | | 1974 | 2,833 | | 1973 | 2,764 | | 1972 | 2,706 | | 1971 | 2,649 | | 1970 | 2,592 | | 1969 | 2,512 | | 1968 | 2,429 | | 1967 | 2,347 | | 1966 | 2,272 | | 1965 | 2,212 | | 1964 | 2,148 | | 1963 | 2,099 | | 1962 | 2,062 | | 1961 | 2,030 | | 1960 | 2,004 |
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