| Year | Value | | 2022 | 22,312 | | 2021 | 21,594 | | 2020 | 20,804 | | 2019 | 20,024 | | 2018 | 19,274 | | 2017 | 18,552 | | 2016 | 17,852 | | 2015 | 17,169 | | 2014 | 16,567 | | 2013 | 16,048 | | 2012 | 15,535 | | 2011 | 14,963 | | 2010 | 14,486 | | 2009 | 14,392 | | 2008 | 14,679 | | 2007 | 15,239 | | 2006 | 15,924 | | 2005 | 16,402 | | 2004 | 16,254 | | 2003 | 15,429 | | 2002 | 14,293 | | 2001 | 13,194 | | 2000 | 12,386 | | 1999 | 12,013 | | 1998 | 12,024 | | 1997 | 12,222 | | 1996 | 12,401 | | 1995 | 12,404 | | 1994 | 12,171 | | 1993 | 11,749 | | 1992 | 11,243 | | 1991 | 10,750 | | 1990 | 10,459 | | 1989 | 10,396 | | 1988 | 10,400 | | 1987 | 10,421 | | 1986 | 10,447 | | 1985 | 10,469 | | 1984 | 10,482 | | 1983 | 10,495 | | 1982 | 10,508 | | 1981 | 10,522 | | 1980 | 10,502 | | 1979 | 10,463 | | 1978 | 10,404 | | 1977 | 10,269 | | 1976 | 10,089 | | 1975 | 9,930 | | 1974 | 9,781 | | 1973 | 9,637 | | 1972 | 9,510 | | 1971 | 9,352 | | 1970 | 9,124 | | 1969 | 8,838 | | 1968 | 8,501 | | 1967 | 8,122 | | 1966 | 7,749 | | 1965 | 7,414 | | 1964 | 7,106 | | 1963 | 6,804 | | 1962 | 6,544 | | 1961 | 6,393 | | 1960 | 6,390 |
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