| Year | Value | | 2022 | 9,465 | | 2021 | 9,358 | | 2020 | 9,291 | | 2019 | 9,292 | | 2018 | 9,465 | | 2017 | 9,755 | | 2016 | 9,923 | | 2015 | 9,935 | | 2014 | 9,911 | | 2013 | 9,835 | | 2012 | 9,718 | | 2011 | 9,674 | | 2010 | 9,760 | | 2009 | 9,912 | | 2008 | 10,077 | | 2007 | 10,308 | | 2006 | 10,550 | | 2005 | 10,687 | | 2004 | 10,708 | | 2003 | 10,652 | | 2002 | 10,530 | | 2001 | 10,501 | | 2000 | 10,696 | | 1999 | 11,037 | | 1998 | 11,414 | | 1997 | 11,716 | | 1996 | 11,926 | | 1995 | 12,072 | | 1994 | 12,152 | | 1993 | 12,174 | | 1992 | 12,152 | | 1991 | 12,079 | | 1990 | 11,952 | | 1989 | 11,821 | | 1988 | 11,655 | | 1987 | 11,396 | | 1986 | 11,058 | | 1985 | 10,670 | | 1984 | 10,216 | | 1983 | 9,731 | | 1982 | 9,246 | | 1981 | 8,717 | | 1980 | 8,141 | | 1979 | 7,617 | | 1978 | 7,122 | | 1977 | 6,600 | | 1976 | 6,131 | | 1975 | 5,737 | | 1974 | 5,427 | | 1973 | 5,217 | | 1972 | 5,146 | | 1971 | 5,206 | | 1970 | 5,375 | | 1969 | 5,645 | | 1968 | 5,964 | | 1967 | 6,264 | | 1966 | 6,535 | | 1965 | 6,803 | | 1964 | 7,050 | | 1963 | 7,271 | | 1962 | 7,464 | | 1961 | 7,611 | | 1960 | 7,644 |
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