| Year | Value | | 2022 | 9,246 | | 2021 | 9,082 | | 2020 | 8,984 | | 2019 | 8,988 | | 2018 | 9,122 | | 2017 | 9,320 | | 2016 | 9,397 | | 2015 | 9,331 | | 2014 | 9,235 | | 2013 | 9,127 | | 2012 | 9,007 | | 2011 | 8,987 | | 2010 | 9,090 | | 2009 | 9,236 | | 2008 | 9,404 | | 2007 | 9,654 | | 2006 | 9,938 | | 2005 | 10,135 | | 2004 | 10,222 | | 2003 | 10,238 | | 2002 | 10,224 | | 2001 | 10,216 | | 2000 | 10,312 | | 1999 | 10,562 | | 1998 | 10,861 | | 1997 | 11,101 | | 1996 | 11,283 | | 1995 | 11,454 | | 1994 | 11,577 | | 1993 | 11,606 | | 1992 | 11,558 | | 1991 | 11,449 | | 1990 | 11,295 | | 1989 | 11,167 | | 1988 | 11,041 | | 1987 | 10,845 | | 1986 | 10,583 | | 1985 | 10,272 | | 1984 | 9,894 | | 1983 | 9,487 | | 1982 | 9,083 | | 1981 | 8,625 | | 1980 | 8,092 | | 1979 | 7,593 | | 1978 | 7,098 | | 1977 | 6,543 | | 1976 | 6,022 | | 1975 | 5,577 | | 1974 | 5,228 | | 1973 | 4,980 | | 1972 | 4,874 | | 1971 | 4,925 | | 1970 | 5,083 | | 1969 | 5,334 | | 1968 | 5,670 | | 1967 | 6,006 | | 1966 | 6,269 | | 1965 | 6,447 | | 1964 | 6,534 | | 1963 | 6,529 | | 1962 | 6,452 | | 1961 | 6,350 | | 1960 | 6,254 |
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