| Year | Value | | 2022 | 3,735 | | 2021 | 3,698 | | 2020 | 3,620 | | 2019 | 3,552 | | 2018 | 3,499 | | 2017 | 3,435 | | 2016 | 3,435 | | 2015 | 3,500 | | 2014 | 3,578 | | 2013 | 3,665 | | 2012 | 3,741 | | 2011 | 3,808 | | 2010 | 3,875 | | 2009 | 3,927 | | 2008 | 3,937 | | 2007 | 3,916 | | 2006 | 3,902 | | 2005 | 3,912 | | 2004 | 3,922 | | 2003 | 3,935 | | 2002 | 3,964 | | 2001 | 4,021 | | 2000 | 4,093 | | 1999 | 4,154 | | 1998 | 4,179 | | 1997 | 4,158 | | 1996 | 4,157 | | 1995 | 4,185 | | 1994 | 4,169 | | 1993 | 4,091 | | 1992 | 3,948 | | 1991 | 3,776 | | 1990 | 3,604 | | 1989 | 3,444 | | 1988 | 3,303 | | 1987 | 3,181 | | 1986 | 3,141 | | 1985 | 3,183 | | 1984 | 3,219 | | 1983 | 3,228 | | 1982 | 3,207 | | 1981 | 3,163 | | 1980 | 3,099 | | 1979 | 3,021 | | 1978 | 2,944 | | 1977 | 2,872 | | 1976 | 2,824 | | 1975 | 2,807 | | 1974 | 2,801 | | 1973 | 2,791 | | 1972 | 2,792 | | 1971 | 2,796 | | 1970 | 2,796 | | 1969 | 2,804 | | 1968 | 2,819 | | 1967 | 2,826 | | 1966 | 2,803 | | 1965 | 2,752 | | 1964 | 2,692 | | 1963 | 2,629 | | 1962 | 2,567 | | 1961 | 2,506 | | 1960 | 2,445 |
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