| Year | Value | | 2022 | 4,152 | | 2021 | 4,097 | | 2020 | 4,056 | | 2019 | 4,012 | | 2018 | 3,995 | | 2017 | 4,029 | | 2016 | 4,116 | | 2015 | 4,207 | | 2014 | 4,247 | | 2013 | 4,237 | | 2012 | 4,200 | | 2011 | 4,140 | | 2010 | 4,069 | | 2009 | 4,019 | | 2008 | 3,993 | | 2007 | 3,970 | | 2006 | 3,949 | | 2005 | 3,935 | | 2004 | 3,914 | | 2003 | 3,904 | | 2002 | 3,897 | | 2001 | 3,896 | | 2000 | 3,943 | | 1999 | 4,022 | | 1998 | 4,076 | | 1997 | 4,091 | | 1996 | 4,113 | | 1995 | 4,212 | | 1994 | 4,320 | | 1993 | 4,337 | | 1992 | 4,276 | | 1991 | 4,138 | | 1990 | 3,976 | | 1989 | 3,835 | | 1988 | 3,746 | | 1987 | 3,681 | | 1986 | 3,606 | | 1985 | 3,586 | | 1984 | 3,585 | | 1983 | 3,550 | | 1982 | 3,496 | | 1981 | 3,425 | | 1980 | 3,394 | | 1979 | 3,426 | | 1978 | 3,471 | | 1977 | 3,513 | | 1976 | 3,581 | | 1975 | 3,727 | | 1974 | 3,909 | | 1973 | 4,047 | | 1972 | 4,159 | | 1971 | 4,271 | | 1970 | 4,365 | | 1969 | 4,416 | | 1968 | 4,445 | | 1967 | 4,442 | | 1966 | 4,387 | | 1965 | 4,317 | | 1964 | 4,253 | | 1963 | 4,183 | | 1962 | 4,098 | | 1961 | 3,976 | | 1960 | 3,834 |
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