| Year | Value | | 2022 | 18,304 | | 2021 | 17,949 | | 2020 | 17,538 | | 2019 | 17,135 | | 2018 | 16,768 | | 2017 | 16,443 | | 2016 | 16,183 | | 2015 | 16,000 | | 2014 | 15,792 | | 2013 | 15,467 | | 2012 | 15,046 | | 2011 | 14,536 | | 2010 | 13,938 | | 2009 | 13,331 | | 2008 | 12,775 | | 2007 | 12,244 | | 2006 | 11,719 | | 2005 | 11,195 | | 2004 | 10,673 | | 2003 | 10,178 | | 2002 | 9,705 | | 2001 | 9,218 | | 2000 | 8,731 | | 1999 | 8,270 | | 1998 | 7,844 | | 1997 | 7,481 | | 1996 | 7,216 | | 1995 | 7,025 | | 1994 | 6,881 | | 1993 | 6,765 | | 1992 | 6,657 | | 1991 | 6,558 | | 1990 | 6,465 | | 1989 | 6,352 | | 1988 | 6,205 | | 1987 | 6,043 | | 1986 | 5,863 | | 1985 | 5,670 | | 1984 | 5,483 | | 1983 | 5,312 | | 1982 | 5,152 | | 1981 | 4,998 | | 1980 | 4,848 | | 1979 | 4,694 | | 1978 | 4,538 | | 1977 | 4,389 | | 1976 | 4,253 | | 1975 | 4,144 | | 1974 | 4,068 | | 1973 | 4,017 | | 1972 | 3,982 | | 1971 | 3,959 | | 1970 | 3,910 | | 1969 | 3,830 | | 1968 | 3,749 | | 1967 | 3,669 | | 1966 | 3,591 | | 1965 | 3,513 | | 1964 | 3,434 | | 1963 | 3,358 | | 1962 | 3,281 | | 1961 | 3,206 | | 1960 | 3,135 |
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