| Year | Value | | 2022 | 20,198 | | 2021 | 19,565 | | 2020 | 18,971 | | 2019 | 18,323 | | 2018 | 17,633 | | 2017 | 17,026 | | 2016 | 16,586 | | 2015 | 16,300 | | 2014 | 16,133 | | 2013 | 16,052 | | 2012 | 15,985 | | 2011 | 15,787 | | 2010 | 15,425 | | 2009 | 14,878 | | 2008 | 14,291 | | 2007 | 13,742 | | 2006 | 13,197 | | 2005 | 12,774 | | 2004 | 12,460 | | 2003 | 12,217 | | 2002 | 12,045 | | 2001 | 11,847 | | 2000 | 11,419 | | 1999 | 10,922 | | 1998 | 10,535 | | 1997 | 10,305 | | 1996 | 10,223 | | 1995 | 10,237 | | 1994 | 10,425 | | 1993 | 10,670 | | 1992 | 10,808 | | 1991 | 10,770 | | 1990 | 10,550 | | 1989 | 10,168 | | 1988 | 9,678 | | 1987 | 9,208 | | 1986 | 8,870 | | 1985 | 8,652 | | 1984 | 8,505 | | 1983 | 8,364 | | 1982 | 8,141 | | 1981 | 7,869 | | 1980 | 7,637 | | 1979 | 7,473 | | 1978 | 7,360 | | 1977 | 7,288 | | 1976 | 7,246 | | 1975 | 7,199 | | 1974 | 7,116 | | 1973 | 7,017 | | 1972 | 6,925 | | 1971 | 6,804 | | 1970 | 6,639 | | 1969 | 6,431 | | 1968 | 6,175 | | 1967 | 5,883 | | 1966 | 5,605 | | 1965 | 5,374 | | 1964 | 5,184 | | 1963 | 5,041 | | 1962 | 4,942 | | 1961 | 4,853 | | 1960 | 4,754 |
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