| Year | Value | | 2022 | 3,619 | | 2021 | 3,568 | | 2020 | 3,507 | | 2019 | 3,462 | | 2018 | 3,427 | | 2017 | 3,400 | | 2016 | 3,415 | | 2015 | 3,457 | | 2014 | 3,479 | | 2013 | 3,485 | | 2012 | 3,492 | | 2011 | 3,519 | | 2010 | 3,569 | | 2009 | 3,638 | | 2008 | 3,716 | | 2007 | 3,780 | | 2006 | 3,797 | | 2005 | 3,786 | | 2004 | 3,762 | | 2003 | 3,719 | | 2002 | 3,655 | | 2001 | 3,557 | | 2000 | 3,434 | | 1999 | 3,314 | | 1998 | 3,200 | | 1997 | 3,066 | | 1996 | 2,918 | | 1995 | 2,768 | | 1994 | 2,614 | | 1993 | 2,466 | | 1992 | 2,333 | | 1991 | 2,218 | | 1990 | 2,120 | | 1989 | 2,027 | | 1988 | 1,938 | | 1987 | 1,849 | | 1986 | 1,759 | | 1985 | 1,673 | | 1984 | 1,586 | | 1983 | 1,504 | | 1982 | 1,434 | | 1981 | 1,373 | | 1980 | 1,326 | | 1979 | 1,298 | | 1978 | 1,286 | | 1977 | 1,292 | | 1976 | 1,310 | | 1975 | 1,337 | | 1974 | 1,370 | | 1973 | 1,407 | | 1972 | 1,443 | | 1971 | 1,475 | | 1970 | 1,501 | | 1969 | 1,526 | | 1968 | 1,541 | | 1967 | 1,520 | | 1966 | 1,476 | | 1965 | 1,423 | | 1964 | 1,372 | | 1963 | 1,350 | | 1962 | 1,358 | | 1961 | 1,371 | | 1960 | 1,382 |
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