| Year | Value | | 2022 | 29,361 | | 2021 | 29,738 | | 2020 | 29,928 | | 2019 | 29,888 | | 2018 | 29,660 | | 2017 | 29,289 | | 2016 | 28,833 | | 2015 | 28,336 | | 2014 | 27,793 | | 2013 | 27,203 | | 2012 | 26,572 | | 2011 | 25,879 | | 2010 | 25,117 | | 2009 | 24,394 | | 2008 | 23,726 | | 2007 | 23,002 | | 2006 | 22,210 | | 2005 | 21,387 | | 2004 | 20,566 | | 2003 | 19,778 | | 2002 | 19,064 | | 2001 | 18,436 | | 2000 | 17,853 | | 1999 | 17,272 | | 1998 | 16,710 | | 1997 | 16,198 | | 1996 | 15,722 | | 1995 | 15,306 | | 1994 | 14,946 | | 1993 | 14,550 | | 1992 | 14,057 | | 1991 | 13,503 | | 1990 | 12,914 | | 1989 | 12,319 | | 1988 | 11,785 | | 1987 | 11,324 | | 1986 | 10,911 | | 1985 | 10,528 | | 1984 | 10,126 | | 1983 | 9,681 | | 1982 | 9,217 | | 1981 | 8,763 | | 1980 | 8,386 | | 1979 | 8,251 | | 1978 | 8,301 | | 1977 | 8,346 | | 1976 | 8,358 | | 1975 | 8,340 | | 1974 | 8,338 | | 1973 | 8,378 | | 1972 | 8,442 | | 1971 | 8,428 | | 1970 | 8,163 | | 1969 | 7,788 | | 1968 | 7,500 | | 1967 | 7,285 | | 1966 | 7,132 | | 1965 | 7,030 | | 1964 | 6,969 | | 1963 | 6,928 | | 1962 | 6,888 | | 1961 | 6,822 | | 1960 | 6,779 |
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