| Year | Value | | 2022 | 6,004 | | 2021 | 6,110 | | 2020 | 6,228 | | 2019 | 6,361 | | 2018 | 6,494 | | 2017 | 6,608 | | 2016 | 6,722 | | 2015 | 6,789 | | 2014 | 6,778 | | 2013 | 6,759 | | 2012 | 6,727 | | 2011 | 6,614 | | 2010 | 6,456 | | 2009 | 6,310 | | 2008 | 6,175 | | 2007 | 6,035 | | 2006 | 5,889 | | 2005 | 5,727 | | 2004 | 5,533 | | 2003 | 5,344 | | 2002 | 5,209 | | 2001 | 5,138 | | 2000 | 5,113 | | 1999 | 5,140 | | 1998 | 5,194 | | 1997 | 5,251 | | 1996 | 5,316 | | 1995 | 5,301 | | 1994 | 5,174 | | 1993 | 4,975 | | 1992 | 4,669 | | 1991 | 4,322 | | 1990 | 4,127 | | 1989 | 4,032 | | 1988 | 3,953 | | 1987 | 3,948 | | 1986 | 4,007 | | 1985 | 4,026 | | 1984 | 3,973 | | 1983 | 3,892 | | 1982 | 3,801 | | 1981 | 3,727 | | 1980 | 3,683 | | 1979 | 3,653 | | 1978 | 3,634 | | 1977 | 3,637 | | 1976 | 3,671 | | 1975 | 3,731 | | 1974 | 3,773 | | 1973 | 3,778 | | 1972 | 3,779 | | 1971 | 3,801 | | 1970 | 3,842 | | 1969 | 3,858 | | 1968 | 3,820 | | 1967 | 3,731 | | 1966 | 3,617 | | 1965 | 3,535 | | 1964 | 3,526 | | 1963 | 3,600 | | 1962 | 3,739 | | 1961 | 3,893 | | 1960 | 4,005 |
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