| Year | Value | | 2022 | 5,989 | | 2021 | 6,015 | | 2020 | 6,077 | | 2019 | 6,058 | | 2018 | 5,917 | | 2017 | 5,767 | | 2016 | 5,653 | | 2015 | 5,544 | | 2014 | 5,465 | | 2013 | 5,447 | | 2012 | 5,508 | | 2011 | 5,672 | | 2010 | 5,863 | | 2009 | 6,058 | | 2008 | 6,244 | | 2007 | 6,387 | | 2006 | 6,486 | | 2005 | 6,518 | | 2004 | 6,493 | | 2003 | 6,496 | | 2002 | 6,492 | | 2001 | 6,405 | | 2000 | 6,301 | | 1999 | 6,199 | | 1998 | 6,064 | | 1997 | 5,918 | | 1996 | 5,801 | | 1995 | 5,693 | | 1994 | 5,561 | | 1993 | 5,408 | | 1992 | 5,275 | | 1991 | 5,196 | | 1990 | 5,182 | | 1989 | 5,234 | | 1988 | 5,318 | | 1987 | 5,403 | | 1986 | 5,455 | | 1985 | 5,364 | | 1984 | 5,141 | | 1983 | 4,882 | | 1982 | 4,564 | | 1981 | 4,231 | | 1980 | 4,013 | | 1979 | 3,913 | | 1978 | 3,883 | | 1977 | 3,904 | | 1976 | 3,938 | | 1975 | 3,924 | | 1974 | 3,856 | | 1973 | 3,766 | | 1972 | 3,663 | | 1971 | 3,556 | | 1970 | 3,504 | | 1969 | 3,514 | | 1968 | 3,534 | | 1967 | 3,552 | | 1966 | 3,558 | | 1965 | 3,550 | | 1964 | 3,531 | | 1963 | 3,527 | | 1962 | 3,571 | | 1961 | 3,655 | | 1960 | 3,703 |
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