| Year | Value | | 2022 | 6,322 | | 2021 | 6,167 | | 2020 | 5,957 | | 2019 | 5,781 | | 2018 | 5,639 | | 2017 | 5,537 | | 2016 | 5,541 | | 2015 | 5,607 | | 2014 | 5,642 | | 2013 | 5,608 | | 2012 | 5,553 | | 2011 | 5,501 | | 2010 | 5,410 | | 2009 | 5,315 | | 2008 | 5,276 | | 2007 | 5,324 | | 2006 | 5,476 | | 2005 | 5,678 | | 2004 | 5,887 | | 2003 | 6,068 | | 2002 | 6,207 | | 2001 | 6,312 | | 2000 | 6,390 | | 1999 | 6,449 | | 1998 | 6,531 | | 1997 | 6,584 | | 1996 | 6,529 | | 1995 | 6,414 | | 1994 | 6,270 | | 1993 | 6,111 | | 1992 | 5,964 | | 1991 | 5,829 | | 1990 | 5,689 | | 1989 | 5,535 | | 1988 | 5,372 | | 1987 | 5,238 | | 1986 | 5,147 | | 1985 | 5,113 | | 1984 | 5,140 | | 1983 | 5,166 | | 1982 | 5,171 | | 1981 | 5,191 | | 1980 | 5,190 | | 1979 | 5,075 | | 1978 | 4,806 | | 1977 | 4,442 | | 1976 | 4,100 | | 1975 | 3,906 | | 1974 | 3,837 | | 1973 | 3,810 | | 1972 | 3,813 | | 1971 | 3,843 | | 1970 | 3,839 | | 1969 | 3,790 | | 1968 | 3,726 | | 1967 | 3,642 | | 1966 | 3,554 | | 1965 | 3,510 | | 1964 | 3,510 | | 1963 | 3,516 | | 1962 | 3,509 | | 1961 | 3,480 | | 1960 | 3,448 |
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