| Year | Value | | 2022 | 34,432 | | 2021 | 32,903 | | 2020 | 31,430 | | 2019 | 30,004 | | 2018 | 28,628 | | 2017 | 27,200 | | 2016 | 25,936 | | 2015 | 25,019 | | 2014 | 24,248 | | 2013 | 23,925 | | 2012 | 24,307 | | 2011 | 24,782 | | 2010 | 24,997 | | 2009 | 25,039 | | 2008 | 24,793 | | 2007 | 24,223 | | 2006 | 23,526 | | 2005 | 23,104 | | 2004 | 23,113 | | 2003 | 23,569 | | 2002 | 24,442 | | 2001 | 25,064 | | 2000 | 25,139 | | 1999 | 24,861 | | 1998 | 24,223 | | 1997 | 23,433 | | 1996 | 22,805 | | 1995 | 22,223 | | 1994 | 21,390 | | 1993 | 20,088 | | 1992 | 18,346 | | 1991 | 16,527 | | 1990 | 14,818 | | 1989 | 13,325 | | 1988 | 12,036 | | 1987 | 10,830 | | 1986 | 9,660 | | 1985 | 8,540 | | 1984 | 7,477 | | 1983 | 6,510 | | 1982 | 5,719 | | 1981 | 5,122 | | 1980 | 4,735 | | 1979 | 4,544 | | 1978 | 4,516 | | 1977 | 4,633 | | 1976 | 4,860 | | 1975 | 5,151 | | 1974 | 5,468 | | 1973 | 5,794 | | 1972 | 6,109 | | 1971 | 6,400 | | 1970 | 6,542 | | 1969 | 6,525 | | 1968 | 6,487 | | 1967 | 6,428 | | 1966 | 6,342 | | 1965 | 6,193 | | 1964 | 6,028 | | 1963 | 5,873 | | 1962 | 5,771 | | 1961 | 5,743 | | 1960 | 5,910 |
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