| Year | Value | | 2019 | 44,750 | | 2018 | 43,892 | | 2017 | 43,648 | | 2016 | 43,478 | | 2015 | 42,954 | | 2014 | 41,665 | | 2013 | 39,928 | | 2012 | 37,901 | | 2011 | 35,949 | | 2010 | 34,331 | | 2009 | 32,707 | | 2008 | 31,420 | | 2007 | 30,415 | | 2006 | 29,550 | | 2005 | 28,730 | | 2004 | 27,835 | | 2003 | 27,096 | | 2002 | 26,500 | | 2001 | 26,029 | | 2000 | 25,663 | | 1999 | 25,177 | | 1998 | 24,825 | | 1997 | 24,582 | | 1996 | 24,401 | | 1995 | 24,232 | | 1994 | 23,766 | | 1993 | 23,331 | | 1992 | 22,938 | | 1991 | 22,614 | | 1990 | 22,365 | | 1989 | 22,054 | | 1988 | 21,835 | | 1987 | 21,693 | | 1986 | 21,594 | | 1985 | 21,503 | | 1984 | 21,386 | | 1983 | 21,306 | | 1982 | 21,251 | | 1981 | 21,203 | | 1980 | 21,129 | | 1979 | 20,912 | | 1978 | 20,682 | | 1977 | 20,439 | | 1976 | 20,177 | | 1975 | 19,879 | | 1974 | 19,475 | | 1973 | 19,044 | | 1972 | 18,601 | | 1971 | 18,177 | | 1970 | 17,796 | | 1969 | 17,428 | | 1968 | 17,173 | | 1967 | 17,000 | | 1966 | 16,838 | | 1965 | 16,613 | | 1964 | 16,561 | | 1963 | 16,481 | | 1962 | 16,376 | | 1961 | 16,293 | | 1960 | 16,255 |
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