| Year | Value | | 2022 | 21,318 | | 2021 | 22,338 | | 2020 | 23,003 | | 2019 | 23,432 | | 2018 | 23,487 | | 2017 | 23,288 | | 2016 | 22,905 | | 2015 | 22,295 | | 2014 | 21,432 | | 2013 | 20,652 | | 2012 | 19,938 | | 2011 | 18,995 | | 2010 | 17,905 | | 2009 | 16,719 | | 2008 | 15,507 | | 2007 | 14,384 | | 2006 | 13,406 | | 2005 | 12,625 | | 2004 | 12,052 | | 2003 | 11,606 | | 2002 | 11,241 | | 2001 | 10,952 | | 2000 | 10,738 | | 1999 | 10,601 | | 1998 | 10,485 | | 1997 | 10,322 | | 1996 | 10,105 | | 1995 | 9,847 | | 1994 | 9,582 | | 1993 | 9,325 | | 1992 | 9,059 | | 1991 | 8,756 | | 1990 | 8,409 | | 1989 | 8,074 | | 1988 | 7,755 | | 1987 | 7,408 | | 1986 | 7,023 | | 1985 | 6,597 | | 1984 | 6,143 | | 1983 | 5,722 | | 1982 | 5,397 | | 1981 | 5,169 | | 1980 | 5,016 | | 1979 | 4,917 | | 1978 | 4,857 | | 1977 | 4,736 | | 1976 | 4,556 | | 1975 | 4,405 | | 1974 | 4,284 | | 1973 | 4,188 | | 1972 | 4,114 | | 1971 | 4,061 | | 1970 | 4,030 | | 1969 | 4,018 | | 1968 | 4,020 | | 1967 | 4,049 | | 1966 | 4,114 | | 1965 | 4,162 | | 1964 | 4,133 | | 1963 | 4,039 | | 1962 | 3,916 | | 1961 | 3,779 | | 1960 | 3,637 |
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