| Year | Value | | 2022 | 4,324 | | 2021 | 4,247 | | 2020 | 4,200 | | 2019 | 4,152 | | 2018 | 4,139 | | 2017 | 4,182 | | 2016 | 4,269 | | 2015 | 4,333 | | 2014 | 4,330 | | 2013 | 4,294 | | 2012 | 4,230 | | 2011 | 4,122 | | 2010 | 4,058 | | 2009 | 4,063 | | 2008 | 4,067 | | 2007 | 4,066 | | 2006 | 4,064 | | 2005 | 4,043 | | 2004 | 4,020 | | 2003 | 4,016 | | 2002 | 4,003 | | 2001 | 4,008 | | 2000 | 4,101 | | 1999 | 4,217 | | 1998 | 4,287 | | 1997 | 4,336 | | 1996 | 4,335 | | 1995 | 4,361 | | 1994 | 4,420 | | 1993 | 4,422 | | 1992 | 4,359 | | 1991 | 4,239 | | 1990 | 4,135 | | 1989 | 4,049 | | 1988 | 3,964 | | 1987 | 3,892 | | 1986 | 3,790 | | 1985 | 3,700 | | 1984 | 3,658 | | 1983 | 3,614 | | 1982 | 3,529 | | 1981 | 3,439 | | 1980 | 3,436 | | 1979 | 3,511 | | 1978 | 3,591 | | 1977 | 3,653 | | 1976 | 3,696 | | 1975 | 3,802 | | 1974 | 3,972 | | 1973 | 4,139 | | 1972 | 4,293 | | 1971 | 4,416 | | 1970 | 4,500 | | 1969 | 4,569 | | 1968 | 4,615 | | 1967 | 4,609 | | 1966 | 4,555 | | 1965 | 4,485 | | 1964 | 4,411 | | 1963 | 4,348 | | 1962 | 4,290 | | 1961 | 4,203 | | 1960 | 4,074 |
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