Year | Value | 2021 | 35,760 | 2020 | 35,380 | 2019 | 35,090 | 2018 | 35,090 | 2017 | 34,880 | 2016 | 34,240 | 2015 | 33,750 | 2014 | 33,750 | 2013 | 33,700 | 2012 | 33,580 | 2011 | 33,110 | 2010 | 32,680 | 2009 | 31,980 | 2008 | 31,840 | 2007 | 31,600 | 2006 | 31,600 | 2005 | 31,500 | 2004 | 31,400 | 2003 | 31,530 | 2002 | 30,280 | 2001 | 29,360 | 2000 | 29,350 | 1999 | 33,370 | 1998 | 33,950 | 1997 | 33,950 | 1996 | 34,800 | 1995 | 34,800 | 1994 | 35,200 | 1993 | 35,480 | 1992 | 33,550 | 1991 | 33,420 | 1990 | 33,200 | 1989 | 33,710 | 1988 | 32,850 | 1987 | 32,850 | 1986 | 32,850 | 1985 | 32,780 | 1984 | 32,770 | 1983 | 32,700 | 1982 | 32,690 | 1981 | 32,640 | 1980 | 32,570 | 1979 | 32,570 | 1978 | 32,570 | 1977 | 32,450 | 1976 | 31,700 | 1975 | 31,350 | 1974 | 30,960 | 1973 | 30,900 | 1972 | 30,800 | 1971 | 30,450 | 1970 | 30,400 | 1969 | 30,300 | 1968 | 30,300 | 1967 | 30,250 | 1966 | 30,150 | 1965 | 30,050 | 1964 | 30,000 | 1963 | 29,950 | 1962 | 29,900 | 1961 | 29,800 |
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