| Year | Value | | 2022 | 6,725 | | 2021 | 6,564 | | 2020 | 6,363 | | 2019 | 6,174 | | 2018 | 5,953 | | 2017 | 5,785 | | 2016 | 5,733 | | 2015 | 5,724 | | 2014 | 5,716 | | 2013 | 5,650 | | 2012 | 5,554 | | 2011 | 5,497 | | 2010 | 5,391 | | 2009 | 5,245 | | 2008 | 5,187 | | 2007 | 5,207 | | 2006 | 5,287 | | 2005 | 5,431 | | 2004 | 5,591 | | 2003 | 5,734 | | 2002 | 5,850 | | 2001 | 5,949 | | 2000 | 6,064 | | 1999 | 6,207 | | 1998 | 6,306 | | 1997 | 6,318 | | 1996 | 6,276 | | 1995 | 6,198 | | 1994 | 6,092 | | 1993 | 5,986 | | 1992 | 5,914 | | 1991 | 5,833 | | 1990 | 5,666 | | 1989 | 5,475 | | 1988 | 5,349 | | 1987 | 5,269 | | 1986 | 5,223 | | 1985 | 5,204 | | 1984 | 5,193 | | 1983 | 5,196 | | 1982 | 5,224 | | 1981 | 5,266 | | 1980 | 5,286 | | 1979 | 5,189 | | 1978 | 4,921 | | 1977 | 4,559 | | 1976 | 4,230 | | 1975 | 4,051 | | 1974 | 4,034 | | 1973 | 4,109 | | 1972 | 4,205 | | 1971 | 4,269 | | 1970 | 4,281 | | 1969 | 4,247 | | 1968 | 4,179 | | 1967 | 4,093 | | 1966 | 3,984 | | 1965 | 3,875 | | 1964 | 3,764 | | 1963 | 3,655 | | 1962 | 3,582 | | 1961 | 3,540 | | 1960 | 3,501 |
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