| Year | Value | | 2022 | 16,769 | | 2021 | 15,927 | | 2020 | 15,157 | | 2019 | 14,386 | | 2018 | 13,479 | | 2017 | 12,543 | | 2016 | 11,983 | | 2015 | 11,918 | | 2014 | 12,012 | | 2013 | 11,943 | | 2012 | 11,676 | | 2011 | 11,528 | | 2010 | 11,549 | | 2009 | 11,767 | | 2008 | 12,069 | | 2007 | 12,045 | | 2006 | 11,562 | | 2005 | 10,902 | | 2004 | 10,520 | | 2003 | 10,347 | | 2002 | 10,211 | | 2001 | 10,168 | | 2000 | 10,218 | | 1999 | 10,288 | | 1998 | 10,382 | | 1997 | 10,567 | | 1996 | 10,701 | | 1995 | 10,779 | | 1994 | 10,907 | | 1993 | 10,904 | | 1992 | 10,867 | | 1991 | 10,852 | | 1990 | 10,724 | | 1989 | 10,566 | | 1988 | 10,395 | | 1987 | 10,140 | | 1986 | 9,838 | | 1985 | 9,669 | | 1984 | 9,540 | | 1983 | 9,272 | | 1982 | 8,977 | | 1981 | 8,752 | | 1980 | 8,499 | | 1979 | 8,197 | | 1978 | 7,924 | | 1977 | 7,635 | | 1976 | 7,272 | | 1975 | 6,825 | | 1974 | 6,350 | | 1973 | 5,978 | | 1972 | 5,719 | | 1971 | 5,562 | | 1970 | 5,579 | | 1969 | 5,666 | | 1968 | 5,722 | | 1967 | 5,771 | | 1966 | 5,863 | | 1965 | 6,011 | | 1964 | 6,135 | | 1963 | 6,211 | | 1962 | 6,238 | | 1961 | 6,165 | | 1960 | 6,042 |
|