| Year | Value | | 2022 | 4,112 | | 2021 | 3,385 | | 2020 | 3,347 | | 2019 | 3,327 | | 2018 | 3,321 | | 2017 | 3,331 | | 2016 | 3,420 | | 2015 | 3,555 | | 2014 | 3,658 | | 2013 | 3,789 | | 2012 | 3,853 | | 2011 | 3,877 | | 2010 | 4,000 | | 2009 | 3,898 | | 2008 | 3,892 | | 2007 | 3,835 | | 2006 | 3,839 | | 2005 | 3,767 | | 2004 | 3,760 | | 2003 | 3,767 | | 2002 | 3,797 | | 2001 | 3,729 | | 2000 | 3,847 | | 1999 | 3,927 | | 1998 | 3,979 | | 1997 | 4,018 | | 1996 | 3,968 | | 1995 | 3,879 | | 1994 | 3,836 | | 1993 | 3,748 | | 1992 | 3,717 | | 1991 | 3,774 | | 1990 | 3,727 | | 1989 | 3,673 | | 1988 | 3,650 | | 1987 | 3,667 | | 1986 | 3,570 | | 1985 | 3,625 | | 1984 | 3,678 | | 1983 | 3,732 | | 1982 | 3,801 | | 1981 | 3,840 | | 1980 | 3,859 | | 1979 | 3,884 | | 1978 | 3,898 | | 1977 | 3,871 | | 1976 | 3,727 | | 1975 | 3,557 | | 1974 | 3,351 | | 1973 | 3,146 | | 1972 | 2,947 | | 1971 | 2,741 | | 1970 | 2,585 | | 1969 | 2,450 | | 1968 | 2,336 | | 1967 | 2,237 | | 1966 | 2,154 | | 1965 | 2,082 | | 1964 | 2,016 | | 1963 | 1,961 | | 1962 | 1,912 | | 1961 | 1,864 | | 1960 | 1,812 |
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