| Year | Value | | 2022 | 19,696 | | 2021 | 21,908 | | 2020 | 23,783 | | 2019 | 25,498 | | 2018 | 26,781 | | 2017 | 27,897 | | 2016 | 28,988 | | 2015 | 30,012 | | 2014 | 30,862 | | 2013 | 31,514 | | 2012 | 31,645 | | 2011 | 30,916 | | 2010 | 29,396 | | 2009 | 27,238 | | 2008 | 24,676 | | 2007 | 21,926 | | 2006 | 19,354 | | 2005 | 17,652 | | 2004 | 16,580 | | 2003 | 15,527 | | 2002 | 14,570 | | 2001 | 13,732 | | 2000 | 13,031 | | 1999 | 12,501 | | 1998 | 12,109 | | 1997 | 11,786 | | 1996 | 11,486 | | 1995 | 11,185 | | 1994 | 10,948 | | 1993 | 10,778 | | 1992 | 10,607 | | 1991 | 10,414 | | 1990 | 10,201 | | 1989 | 10,017 | | 1988 | 9,871 | | 1987 | 9,723 | | 1986 | 9,551 | | 1985 | 9,313 | | 1984 | 8,952 | | 1983 | 8,525 | | 1982 | 8,099 | | 1981 | 7,678 | | 1980 | 7,288 | | 1979 | 6,948 | | 1978 | 6,671 | | 1977 | 6,426 | | 1976 | 6,169 | | 1975 | 5,908 | | 1974 | 5,661 | | 1973 | 5,410 | | 1972 | 5,167 | | 1971 | 4,974 | | 1970 | 4,838 | | 1969 | 4,741 | | 1968 | 4,669 | | 1967 | 4,657 | | 1966 | 4,774 | | 1965 | 4,972 | | 1964 | 5,078 | | 1963 | 5,081 | | 1962 | 5,067 | | 1961 | 5,040 | | 1960 | 4,999 |
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