| Year | Value | | 2022 | 6,954 | | 2021 | 6,917 | | 2020 | 6,899 | | 2019 | 6,952 | | 2018 | 7,076 | | 2017 | 7,210 | | 2016 | 7,335 | | 2015 | 7,433 | | 2014 | 7,492 | | 2013 | 7,516 | | 2012 | 7,524 | | 2011 | 7,532 | | 2010 | 7,552 | | 2009 | 7,569 | | 2008 | 7,539 | | 2007 | 7,453 | | 2006 | 7,321 | | 2005 | 7,160 | | 2004 | 6,973 | | 2003 | 6,802 | | 2002 | 6,668 | | 2001 | 6,537 | | 2000 | 6,424 | | 1999 | 6,346 | | 1998 | 6,296 | | 1997 | 6,267 | | 1996 | 6,258 | | 1995 | 6,231 | | 1994 | 6,164 | | 1993 | 6,105 | | 1992 | 6,082 | | 1991 | 6,163 | | 1990 | 6,531 | | 1989 | 7,119 | | 1988 | 7,569 | | 1987 | 7,720 | | 1986 | 7,625 | | 1985 | 7,323 | | 1984 | 6,901 | | 1983 | 6,525 | | 1982 | 6,233 | | 1981 | 6,014 | | 1980 | 5,958 | | 1979 | 6,105 | | 1978 | 6,286 | | 1977 | 6,327 | | 1976 | 6,200 | | 1975 | 5,909 | | 1974 | 5,492 | | 1973 | 5,019 | | 1972 | 4,586 | | 1971 | 4,294 | | 1970 | 4,275 | | 1969 | 4,638 | | 1968 | 5,238 | | 1967 | 5,814 | | 1966 | 6,187 | | 1965 | 6,233 | | 1964 | 5,904 | | 1963 | 5,278 | | 1962 | 4,524 | | 1961 | 3,801 | | 1960 | 3,212 |
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