| Year | Value | | 2022 | 21,009 | | 2021 | 19,708 | | 2020 | 18,426 | | 2019 | 17,062 | | 2018 | 16,007 | | 2017 | 15,258 | | 2016 | 14,512 | | 2015 | 13,807 | | 2014 | 13,303 | | 2013 | 12,927 | | 2012 | 12,547 | | 2011 | 12,213 | | 2010 | 11,882 | | 2009 | 11,554 | | 2008 | 11,268 | | 2007 | 11,046 | | 2006 | 10,912 | | 2005 | 10,814 | | 2004 | 10,711 | | 2003 | 10,619 | | 2002 | 10,509 | | 2001 | 10,393 | | 2000 | 10,296 | | 1999 | 10,213 | | 1998 | 10,153 | | 1997 | 10,104 | | 1996 | 10,051 | | 1995 | 9,980 | | 1994 | 9,859 | | 1993 | 9,676 | | 1992 | 9,482 | | 1991 | 9,350 | | 1990 | 9,332 | | 1989 | 9,459 | | 1988 | 9,873 | | 1987 | 10,568 | | 1986 | 11,292 | | 1985 | 11,918 | | 1984 | 12,451 | | 1983 | 12,895 | | 1982 | 13,262 | | 1981 | 13,579 | | 1980 | 13,859 | | 1979 | 14,090 | | 1978 | 14,254 | | 1977 | 14,352 | | 1976 | 14,387 | | 1975 | 14,257 | | 1974 | 14,021 | | 1973 | 13,837 | | 1972 | 13,686 | | 1971 | 13,513 | | 1970 | 13,276 | | 1969 | 12,974 | | 1968 | 12,602 | | 1967 | 12,187 | | 1966 | 11,812 | | 1965 | 11,532 | | 1964 | 11,344 | | 1963 | 11,249 | | 1962 | 11,246 | | 1961 | 11,289 | | 1960 | 11,341 |
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