| Year | Value | | 2022 | 15,659 | | 2021 | 15,273 | | 2020 | 14,763 | | 2019 | 14,437 | | 2018 | 14,385 | | 2017 | 14,334 | | 2016 | 14,324 | | 2015 | 14,414 | | 2014 | 14,190 | | 2013 | 13,726 | | 2012 | 13,540 | | 2011 | 13,538 | | 2010 | 13,648 | | 2009 | 13,886 | | 2008 | 14,207 | | 2007 | 14,557 | | 2006 | 14,977 | | 2005 | 15,446 | | 2004 | 15,851 | | 2003 | 16,150 | | 2002 | 16,303 | | 2001 | 16,274 | | 2000 | 16,073 | | 1999 | 15,756 | | 1998 | 15,381 | | 1997 | 14,990 | | 1996 | 14,621 | | 1995 | 14,281 | | 1994 | 13,956 | | 1993 | 13,667 | | 1992 | 13,416 | | 1991 | 13,191 | | 1990 | 13,007 | | 1989 | 12,849 | | 1988 | 12,679 | | 1987 | 12,480 | | 1986 | 12,230 | | 1985 | 11,902 | | 1984 | 11,503 | | 1983 | 11,066 | | 1982 | 10,612 | | 1981 | 10,151 | | 1980 | 9,701 | | 1979 | 9,263 | | 1978 | 8,836 | | 1977 | 8,421 | | 1976 | 8,030 | | 1975 | 7,670 | | 1974 | 7,357 | | 1973 | 7,098 | | 1972 | 6,883 | | 1971 | 6,706 | | 1970 | 6,542 | | 1969 | 6,372 | | 1968 | 6,204 | | 1967 | 6,039 | | 1966 | 5,873 | | 1965 | 5,716 | | 1964 | 5,574 | | 1963 | 5,424 | | 1962 | 5,257 | | 1961 | 5,064 | | 1960 | 4,868 |
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