| Year | Value | | 2022 | 20,540 | | 2021 | 20,166 | | 2020 | 19,782 | | 2019 | 19,434 | | 2018 | 19,107 | | 2017 | 18,769 | | 2016 | 18,409 | | 2015 | 18,019 | | 2014 | 17,625 | | 2013 | 17,259 | | 2012 | 16,937 | | 2011 | 16,684 | | 2010 | 16,520 | | 2009 | 16,341 | | 2008 | 16,052 | | 2007 | 15,668 | | 2006 | 15,181 | | 2005 | 14,595 | | 2004 | 13,988 | | 2003 | 13,425 | | 2002 | 12,881 | | 2001 | 12,341 | | 2000 | 11,797 | | 1999 | 11,213 | | 1998 | 10,621 | | 1997 | 10,059 | | 1996 | 9,493 | | 1995 | 8,943 | | 1994 | 8,452 | | 1993 | 8,018 | | 1992 | 7,650 | | 1991 | 7,385 | | 1990 | 7,197 | | 1989 | 7,060 | | 1988 | 6,950 | | 1987 | 6,848 | | 1986 | 6,750 | | 1985 | 6,650 | | 1984 | 6,524 | | 1983 | 6,364 | | 1982 | 6,190 | | 1981 | 6,000 | | 1980 | 5,801 | | 1979 | 5,611 | | 1978 | 5,441 | | 1977 | 5,283 | | 1976 | 5,139 | | 1975 | 5,021 | | 1974 | 4,925 | | 1973 | 4,843 | | 1972 | 4,775 | | 1971 | 4,720 | | 1970 | 4,632 | | 1969 | 4,512 | | 1968 | 4,403 | | 1967 | 4,304 | | 1966 | 4,215 | | 1965 | 4,133 | | 1964 | 4,054 | | 1963 | 3,976 | | 1962 | 3,898 | | 1961 | 3,821 | | 1960 | 3,746 |
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