| Year | Value | | 2022 | 2,421 | | 2021 | 2,313 | | 2020 | 2,198 | | 2019 | 2,083 | | 2018 | 1,978 | | 2017 | 1,881 | | 2016 | 1,802 | | 2015 | 1,751 | | 2014 | 1,726 | | 2013 | 1,723 | | 2012 | 1,737 | | 2011 | 1,759 | | 2010 | 1,784 | | 2009 | 1,807 | | 2008 | 1,817 | | 2007 | 1,813 | | 2006 | 1,783 | | 2005 | 1,728 | | 2004 | 1,672 | | 2003 | 1,621 | | 2002 | 1,582 | | 2001 | 1,560 | | 2000 | 1,547 | | 1999 | 1,540 | | 1998 | 1,539 | | 1997 | 1,538 | | 1996 | 1,543 | | 1995 | 1,553 | | 1994 | 1,558 | | 1993 | 1,557 | | 1992 | 1,540 | | 1991 | 1,487 | | 1990 | 1,403 | | 1989 | 1,300 | | 1988 | 1,189 | | 1987 | 1,086 | | 1986 | 1,030 | | 1985 | 1,025 | | 1984 | 1,026 | | 1983 | 1,020 | | 1982 | 997 | | 1981 | 964 | | 1980 | 937 | | 1979 | 920 | | 1978 | 906 | | 1977 | 890 | | 1976 | 857 | | 1975 | 813 | | 1974 | 785 | | 1973 | 779 | | 1972 | 780 | | 1971 | 781 | | 1970 | 783 | | 1969 | 782 | | 1968 | 778 | | 1967 | 774 | | 1966 | 751 | | 1965 | 706 | | 1964 | 662 | | 1963 | 620 | | 1962 | 578 | | 1961 | 553 | | 1960 | 547 |
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