| Year | Value | | 2022 | 3,433 | | 2021 | 3,512 | | 2020 | 3,564 | | 2019 | 3,623 | | 2018 | 3,691 | | 2017 | 3,709 | | 2016 | 3,683 | | 2015 | 3,669 | | 2014 | 3,665 | | 2013 | 3,650 | | 2012 | 3,651 | | 2011 | 3,667 | | 2010 | 3,642 | | 2009 | 3,585 | | 2008 | 3,533 | | 2007 | 3,472 | | 2006 | 3,391 | | 2005 | 3,309 | | 2004 | 3,257 | | 2003 | 3,227 | | 2002 | 3,208 | | 2001 | 3,223 | | 2000 | 3,251 | | 1999 | 3,243 | | 1998 | 3,206 | | 1997 | 3,160 | | 1996 | 3,128 | | 1995 | 3,112 | | 1994 | 3,111 | | 1993 | 3,117 | | 1992 | 3,116 | | 1991 | 3,129 | | 1990 | 3,236 | | 1989 | 3,405 | | 1988 | 3,558 | | 1987 | 3,696 | | 1986 | 3,822 | | 1985 | 3,934 | | 1984 | 4,015 | | 1983 | 4,025 | | 1982 | 3,965 | | 1981 | 3,870 | | 1980 | 3,738 | | 1979 | 3,580 | | 1978 | 3,408 | | 1977 | 3,233 | | 1976 | 3,077 | | 1975 | 2,956 | | 1974 | 2,878 | | 1973 | 2,845 | | 1972 | 2,836 | | 1971 | 2,821 | | 1970 | 2,772 | | 1969 | 2,689 | | 1968 | 2,612 | | 1967 | 2,568 | | 1966 | 2,562 | | 1965 | 2,587 | | 1964 | 2,630 | | 1963 | 2,648 | | 1962 | 2,629 | | 1961 | 2,606 | | 1960 | 2,560 |
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