Year | Value | 2022 | 20,458 | 2021 | 20,429 | 2020 | 20,399 | 2019 | 20,436 | 2018 | 20,394 | 2017 | 20,232 | 2016 | 19,983 | 2015 | 19,756 | 2014 | 19,526 | 2013 | 19,057 | 2012 | 18,474 | 2011 | 17,869 | 2010 | 16,686 | 2009 | 15,155 | 2008 | 14,109 | 2007 | 13,489 | 2006 | 13,317 | 2005 | 13,941 | 2004 | 15,005 | 2003 | 15,921 | 2002 | 16,535 | 2001 | 16,878 | 2000 | 16,858 | 1999 | 16,561 | 1998 | 16,117 | 1997 | 15,669 | 1996 | 15,343 | 1995 | 15,217 | 1994 | 15,246 | 1993 | 15,262 | 1992 | 15,051 | 1991 | 14,403 | 1990 | 13,394 | 1989 | 12,283 | 1988 | 11,275 | 1987 | 10,497 | 1986 | 9,972 | 1985 | 9,601 | 1984 | 9,250 | 1983 | 8,870 | 1982 | 8,512 | 1981 | 8,328 | 1980 | 8,468 | 1979 | 8,920 | 1978 | 9,526 | 1977 | 10,119 | 1976 | 10,547 | 1975 | 10,716 | 1974 | 10,636 | 1973 | 10,387 | 1972 | 10,044 | 1971 | 9,647 | 1970 | 9,199 | 1969 | 8,773 | 1968 | 8,452 | 1967 | 8,265 | 1966 | 8,225 | 1965 | 8,331 | 1964 | 8,537 | 1963 | 8,764 | 1962 | 8,936 | 1961 | 8,972 | 1960 | 8,766 |
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