| Year | Value | | 2022 | 6,479 | | 2021 | 6,455 | | 2020 | 6,396 | | 2019 | 6,385 | | 2018 | 6,429 | | 2017 | 6,449 | | 2016 | 6,437 | | 2015 | 6,395 | | 2014 | 6,322 | | 2013 | 6,231 | | 2012 | 6,139 | | 2011 | 6,070 | | 2010 | 6,040 | | 2009 | 6,022 | | 2008 | 6,008 | | 2007 | 6,011 | | 2006 | 6,017 | | 2005 | 6,017 | | 2004 | 6,017 | | 2003 | 6,036 | | 2002 | 6,074 | | 2001 | 6,125 | | 2000 | 6,186 | | 1999 | 6,211 | | 1998 | 6,215 | | 1997 | 6,248 | | 1996 | 6,284 | | 1995 | 6,302 | | 1994 | 6,306 | | 1993 | 6,282 | | 1992 | 6,239 | | 1991 | 6,244 | | 1990 | 6,340 | | 1989 | 6,443 | | 1988 | 6,457 | | 1987 | 6,368 | | 1986 | 6,195 | | 1985 | 5,968 | | 1984 | 5,716 | | 1983 | 5,490 | | 1982 | 5,346 | | 1981 | 5,322 | | 1980 | 5,356 | | 1979 | 5,339 | | 1978 | 5,261 | | 1977 | 5,143 | | 1976 | 4,968 | | 1975 | 4,773 | | 1974 | 4,592 | | 1973 | 4,406 | | 1972 | 4,225 | | 1971 | 4,053 | | 1970 | 3,882 | | 1969 | 3,712 | | 1968 | 3,514 | | 1967 | 3,274 | | 1966 | 3,034 | | 1965 | 2,832 | | 1964 | 2,671 | | 1963 | 2,556 | | 1962 | 2,480 | | 1961 | 2,416 | | 1960 | 2,343 |
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