| Year | Value | | 2022 | 21,399 | | 2021 | 20,776 | | 2020 | 20,107 | | 2019 | 19,262 | | 2018 | 18,609 | | 2017 | 18,748 | | 2016 | 19,361 | | 2015 | 19,506 | | 2014 | 19,532 | | 2013 | 19,373 | | 2012 | 18,597 | | 2011 | 17,724 | | 2010 | 16,699 | | 2009 | 15,746 | | 2008 | 14,948 | | 2007 | 14,123 | | 2006 | 13,314 | | 2005 | 12,543 | | 2004 | 11,814 | | 2003 | 11,120 | | 2002 | 10,464 | | 2001 | 9,832 | | 2000 | 9,213 | | 1999 | 8,630 | | 1998 | 8,475 | | 1997 | 8,425 | | 1996 | 8,115 | | 1995 | 7,851 | | 1994 | 7,494 | | 1993 | 7,239 | | 1992 | 7,177 | | 1991 | 7,023 | | 1990 | 6,784 | | 1989 | 6,669 | | 1988 | 7,277 | | 1987 | 7,925 | | 1986 | 7,865 | | 1985 | 7,672 | | 1984 | 7,492 | | 1983 | 7,292 | | 1982 | 7,044 | | 1981 | 6,774 | | 1980 | 6,511 | | 1979 | 6,260 | | 1978 | 6,016 | | 1977 | 5,779 | | 1976 | 5,562 | | 1975 | 5,376 | | 1974 | 5,218 | | 1973 | 5,093 | | 1972 | 5,058 | | 1971 | 5,087 | | 1970 | 5,200 | | 1969 | 5,401 | | 1968 | 5,585 | | 1967 | 5,754 | | 1966 | 5,949 | | 1965 | 6,103 | | 1964 | 6,136 | | 1963 | 6,187 | | 1962 | 6,269 | | 1961 | 6,314 | | 1960 | 6,376 |
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