| Year | Value | | 2019 | 2,750 | | 2018 | 2,721 | | 2017 | 2,711 | | 2016 | 2,713 | | 2015 | 2,729 | | 2014 | 2,789 | | 2013 | 2,826 | | 2012 | 2,817 | | 2011 | 2,758 | | 2010 | 2,661 | | 2009 | 2,647 | | 2008 | 2,608 | | 2007 | 2,526 | | 2006 | 2,432 | | 2005 | 2,360 | | 2004 | 2,266 | | 2003 | 2,229 | | 2002 | 2,231 | | 2001 | 2,230 | | 2000 | 2,217 | | 1999 | 2,245 | | 1998 | 2,260 | | 1997 | 2,264 | | 1996 | 2,263 | | 1995 | 2,256 | | 1994 | 2,198 | | 1993 | 2,131 | | 1992 | 2,061 | | 1991 | 1,998 | | 1990 | 1,942 | | 1989 | 1,940 | | 1988 | 1,934 | | 1987 | 1,914 | | 1986 | 1,895 | | 1985 | 1,894 | | 1984 | 1,938 | | 1983 | 2,002 | | 1982 | 2,063 | | 1981 | 2,110 | | 1980 | 2,142 | | 1979 | 2,114 | | 1978 | 2,080 | | 1977 | 2,036 | | 1976 | 1,989 | | 1975 | 1,940 | | 1974 | 1,907 | | 1973 | 1,886 | | 1972 | 1,869 | | 1971 | 1,849 | | 1970 | 1,821 | | 1969 | 1,817 | | 1968 | 1,806 | | 1967 | 1,785 | | 1966 | 1,751 | | 1965 | 1,702 | | 1964 | 1,605 | | 1963 | 1,501 | | 1962 | 1,400 | | 1961 | 1,314 | | 1960 | 1,253 |
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