| Year | Value | | 2022 | 4,679 | | 2021 | 4,548 | | 2020 | 4,430 | | 2019 | 4,376 | | 2018 | 4,404 | | 2017 | 4,439 | | 2016 | 4,457 | | 2015 | 4,463 | | 2014 | 4,457 | | 2013 | 4,415 | | 2012 | 4,364 | | 2011 | 4,397 | | 2010 | 4,483 | | 2009 | 4,571 | | 2008 | 4,670 | | 2007 | 4,725 | | 2006 | 4,746 | | 2005 | 4,756 | | 2004 | 4,741 | | 2003 | 4,712 | | 2002 | 4,677 | | 2001 | 4,628 | | 2000 | 4,562 | | 1999 | 4,493 | | 1998 | 4,441 | | 1997 | 4,414 | | 1996 | 4,447 | | 1995 | 4,547 | | 1994 | 4,677 | | 1993 | 4,815 | | 1992 | 4,947 | | 1991 | 5,038 | | 1990 | 5,060 | | 1989 | 5,005 | | 1988 | 4,867 | | 1987 | 4,664 | | 1986 | 4,473 | | 1985 | 4,354 | | 1984 | 4,294 | | 1983 | 4,270 | | 1982 | 4,257 | | 1981 | 4,240 | | 1980 | 4,207 | | 1979 | 4,147 | | 1978 | 4,056 | | 1977 | 3,941 | | 1976 | 3,831 | | 1975 | 3,739 | | 1974 | 3,657 | | 1973 | 3,572 | | 1972 | 3,476 | | 1971 | 3,401 | | 1970 | 3,360 | | 1969 | 3,329 | | 1968 | 3,298 | | 1967 | 3,275 | | 1966 | 3,222 | | 1965 | 3,133 | | 1964 | 3,051 | | 1963 | 2,983 | | 1962 | 2,923 | | 1961 | 2,868 | | 1960 | 2,819 |
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