| Year | Value | | 2022 | 32,351 | | 2021 | 32,317 | | 2020 | 31,865 | | 2019 | 31,148 | | 2018 | 30,267 | | 2017 | 29,260 | | 2016 | 28,105 | | 2015 | 26,777 | | 2014 | 25,386 | | 2013 | 24,034 | | 2012 | 22,634 | | 2011 | 21,111 | | 2010 | 19,716 | | 2009 | 18,750 | | 2008 | 18,129 | | 2007 | 17,701 | | 2006 | 17,360 | | 2005 | 16,965 | | 2004 | 16,421 | | 2003 | 15,780 | | 2002 | 15,143 | | 2001 | 14,663 | | 2000 | 14,568 | | 1999 | 14,974 | | 1998 | 16,019 | | 1997 | 17,487 | | 1996 | 18,854 | | 1995 | 19,957 | | 1994 | 20,857 | | 1993 | 21,453 | | 1992 | 21,778 | | 1991 | 21,874 | | 1990 | 21,652 | | 1989 | 21,004 | | 1988 | 19,873 | | 1987 | 18,527 | | 1986 | 17,228 | | 1985 | 15,993 | | 1984 | 14,871 | | 1983 | 13,849 | | 1982 | 12,802 | | 1981 | 11,714 | | 1980 | 10,672 | | 1979 | 9,620 | | 1978 | 8,482 | | 1977 | 7,355 | | 1976 | 6,353 | | 1975 | 5,581 | | 1974 | 5,088 | | 1973 | 4,867 | | 1972 | 4,887 | | 1971 | 5,080 | | 1970 | 5,328 | | 1969 | 5,528 | | 1968 | 5,662 | | 1967 | 5,756 | | 1966 | 5,785 | | 1965 | 5,752 | | 1964 | 5,692 | | 1963 | 5,571 | | 1962 | 5,400 | | 1961 | 5,229 | | 1960 | 5,379 |
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