| Year | Value | | 2022 | 23,405 | | 2021 | 22,241 | | 2020 | 21,315 | | 2019 | 20,622 | | 2018 | 20,088 | | 2017 | 19,629 | | 2016 | 19,278 | | 2015 | 18,938 | | 2014 | 18,489 | | 2013 | 17,982 | | 2012 | 17,458 | | 2011 | 16,962 | | 2010 | 16,523 | | 2009 | 16,145 | | 2008 | 15,824 | | 2007 | 15,542 | | 2006 | 15,279 | | 2005 | 14,951 | | 2004 | 14,477 | | 2003 | 13,941 | | 2002 | 13,446 | | 2001 | 13,006 | | 2000 | 12,622 | | 1999 | 12,421 | | 1998 | 12,368 | | 1997 | 12,416 | | 1996 | 12,581 | | 1995 | 12,760 | | 1994 | 12,915 | | 1993 | 13,093 | | 1992 | 13,833 | | 1991 | 14,376 | | 1990 | 14,116 | | 1989 | 13,730 | | 1988 | 13,335 | | 1987 | 12,954 | | 1986 | 12,580 | | 1985 | 12,205 | | 1984 | 11,829 | | 1983 | 11,447 | | 1982 | 11,059 | | 1981 | 10,668 | | 1980 | 10,279 | | 1979 | 9,889 | | 1978 | 9,492 | | 1977 | 9,096 | | 1976 | 8,709 | | 1975 | 8,333 | | 1974 | 7,972 | | 1973 | 7,619 | | 1972 | 7,279 | | 1971 | 6,955 | | 1970 | 6,642 | | 1969 | 6,343 | | 1968 | 6,062 | | 1967 | 5,801 | | 1966 | 5,557 | | 1965 | 5,327 | | 1964 | 5,112 | | 1963 | 4,912 | | 1962 | 4,726 | | 1961 | 4,557 | | 1960 | 4,407 |
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