| Year | Value | | 2022 | 3,968 | | 2021 | 4,001 | | 2020 | 3,967 | | 2019 | 3,881 | | 2018 | 3,786 | | 2017 | 3,695 | | 2016 | 3,653 | | 2015 | 3,693 | | 2014 | 3,807 | | 2013 | 3,969 | | 2012 | 4,144 | | 2011 | 4,307 | | 2010 | 4,425 | | 2009 | 4,477 | | 2008 | 4,489 | | 2007 | 4,493 | | 2006 | 4,501 | | 2005 | 4,526 | | 2004 | 4,564 | | 2003 | 4,588 | | 2002 | 4,578 | | 2001 | 4,539 | | 2000 | 4,485 | | 1999 | 4,424 | | 1998 | 4,378 | | 1997 | 4,368 | | 1996 | 4,396 | | 1995 | 4,456 | | 1994 | 4,541 | | 1993 | 4,629 | | 1992 | 4,694 | | 1991 | 4,729 | | 1990 | 4,763 | | 1989 | 4,791 | | 1988 | 4,783 | | 1987 | 4,734 | | 1986 | 4,634 | | 1985 | 4,479 | | 1984 | 4,284 | | 1983 | 4,071 | | 1982 | 3,851 | | 1981 | 3,638 | | 1980 | 3,497 | | 1979 | 3,436 | | 1978 | 3,336 | | 1977 | 3,179 | | 1976 | 3,007 | | 1975 | 2,805 | | 1974 | 2,573 | | 1973 | 2,388 | | 1972 | 2,277 | | 1971 | 2,212 | | 1970 | 2,207 | | 1969 | 2,253 | | 1968 | 2,325 | | 1967 | 2,406 | | 1966 | 2,477 | | 1965 | 2,532 | | 1964 | 2,580 | | 1963 | 2,624 | | 1962 | 2,662 | | 1961 | 2,691 | | 1960 | 2,717 |
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