| Year | Value | | 2022 | 19,146 | | 2021 | 18,357 | | 2020 | 17,608 | | 2019 | 16,935 | | 2018 | 16,372 | | 2017 | 15,914 | | 2016 | 15,546 | | 2015 | 15,271 | | 2014 | 14,958 | | 2013 | 14,573 | | 2012 | 14,270 | | 2011 | 14,107 | | 2010 | 14,278 | | 2009 | 14,751 | | 2008 | 14,962 | | 2007 | 14,481 | | 2006 | 13,319 | | 2005 | 11,730 | | 2004 | 10,506 | | 2003 | 10,333 | | 2002 | 10,829 | | 2001 | 11,394 | | 2000 | 11,800 | | 1999 | 11,908 | | 1998 | 11,659 | | 1997 | 11,159 | | 1996 | 10,586 | | 1995 | 10,050 | | 1994 | 9,603 | | 1993 | 9,239 | | 1992 | 8,910 | | 1991 | 8,568 | | 1990 | 8,260 | | 1989 | 8,056 | | 1988 | 7,976 | | 1987 | 7,968 | | 1986 | 7,971 | | 1985 | 7,980 | | 1984 | 8,002 | | 1983 | 8,054 | | 1982 | 8,143 | | 1981 | 8,278 | | 1980 | 8,315 | | 1979 | 8,228 | | 1978 | 8,147 | | 1977 | 8,064 | | 1976 | 7,964 | | 1975 | 7,834 | | 1974 | 7,674 | | 1973 | 7,454 | | 1972 | 7,175 | | 1971 | 6,915 | | 1970 | 6,708 | | 1969 | 6,544 | | 1968 | 6,420 | | 1967 | 6,333 | | 1966 | 6,259 | | 1965 | 6,178 | | 1964 | 6,094 | | 1963 | 6,014 | | 1962 | 5,920 | | 1961 | 5,803 | | 1960 | 5,664 |
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