| Year | Value | | 2022 | 3,999 | | 2021 | 3,971 | | 2020 | 3,891 | | 2019 | 3,813 | | 2018 | 3,749 | | 2017 | 3,708 | | 2016 | 3,753 | | 2015 | 3,838 | | 2014 | 3,934 | | 2013 | 4,081 | | 2012 | 4,199 | | 2011 | 4,210 | | 2010 | 4,156 | | 2009 | 4,099 | | 2008 | 4,016 | | 2007 | 3,917 | | 2006 | 3,862 | | 2005 | 3,846 | | 2004 | 3,838 | | 2003 | 3,838 | | 2002 | 3,852 | | 2001 | 3,891 | | 2000 | 3,947 | | 1999 | 3,994 | | 1998 | 4,003 | | 1997 | 3,961 | | 1996 | 3,932 | | 1995 | 3,937 | | 1994 | 3,922 | | 1993 | 3,869 | | 1992 | 3,779 | | 1991 | 3,674 | | 1990 | 3,564 | | 1989 | 3,449 | | 1988 | 3,338 | | 1987 | 3,234 | | 1986 | 3,203 | | 1985 | 3,249 | | 1984 | 3,288 | | 1983 | 3,301 | | 1982 | 3,285 | | 1981 | 3,240 | | 1980 | 3,172 | | 1979 | 3,099 | | 1978 | 3,033 | | 1977 | 2,972 | | 1976 | 2,930 | | 1975 | 2,909 | | 1974 | 2,885 | | 1973 | 2,856 | | 1972 | 2,843 | | 1971 | 2,829 | | 1970 | 2,799 | | 1969 | 2,774 | | 1968 | 2,755 | | 1967 | 2,734 | | 1966 | 2,701 | | 1965 | 2,660 | | 1964 | 2,617 | | 1963 | 2,575 | | 1962 | 2,532 | | 1961 | 2,490 | | 1960 | 2,448 |
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