| Year | Value | | 2022 | 23,387 | | 2021 | 22,971 | | 2020 | 22,407 | | 2019 | 21,701 | | 2018 | 20,982 | | 2017 | 20,349 | | 2016 | 19,775 | | 2015 | 19,256 | | 2014 | 18,774 | | 2013 | 18,313 | | 2012 | 17,922 | | 2011 | 17,624 | | 2010 | 17,357 | | 2009 | 17,082 | | 2008 | 16,782 | | 2007 | 16,375 | | 2006 | 15,838 | | 2005 | 15,251 | | 2004 | 14,672 | | 2003 | 14,127 | | 2002 | 13,683 | | 2001 | 13,307 | | 2000 | 12,864 | | 1999 | 12,358 | | 1998 | 11,852 | | 1997 | 11,378 | | 1996 | 10,945 | | 1995 | 10,562 | | 1994 | 10,242 | | 1993 | 9,991 | | 1992 | 9,843 | | 1991 | 9,793 | | 1990 | 9,741 | | 1989 | 9,429 | | 1988 | 9,069 | | 1987 | 8,888 | | 1986 | 8,721 | | 1985 | 8,587 | | 1984 | 8,474 | | 1983 | 8,365 | | 1982 | 8,262 | | 1981 | 8,215 | | 1980 | 8,203 | | 1979 | 8,137 | | 1978 | 8,090 | | 1977 | 8,044 | | 1976 | 7,941 | | 1975 | 7,823 | | 1974 | 7,691 | | 1973 | 7,557 | | 1972 | 7,426 | | 1971 | 7,309 | | 1970 | 7,216 | | 1969 | 7,151 | | 1968 | 7,113 | | 1967 | 7,087 | | 1966 | 7,051 | | 1965 | 6,993 | | 1964 | 6,915 | | 1963 | 6,816 | | 1962 | 6,696 | | 1961 | 6,556 | | 1960 | 6,397 |
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