| Year | Value | | 2022 | 12,593 | | 2021 | 12,961 | | 2020 | 13,255 | | 2019 | 13,257 | | 2018 | 13,084 | | 2017 | 12,915 | | 2016 | 12,781 | | 2015 | 12,698 | | 2014 | 12,654 | | 2013 | 12,636 | | 2012 | 12,640 | | 2011 | 12,657 | | 2010 | 12,682 | | 2009 | 12,710 | | 2008 | 12,729 | | 2007 | 12,739 | | 2006 | 12,748 | | 2005 | 12,754 | | 2004 | 12,751 | | 2003 | 12,745 | | 2002 | 12,733 | | 2001 | 12,699 | | 2000 | 12,636 | | 1999 | 12,548 | | 1998 | 12,429 | | 1997 | 12,280 | | 1996 | 12,116 | | 1995 | 11,945 | | 1994 | 11,763 | | 1993 | 11,569 | | 1992 | 11,360 | | 1991 | 11,133 | | 1990 | 10,888 | | 1989 | 10,624 | | 1988 | 10,342 | | 1987 | 10,047 | | 1986 | 9,751 | | 1985 | 9,464 | | 1984 | 9,185 | | 1983 | 8,915 | | 1982 | 8,651 | | 1981 | 8,380 | | 1980 | 8,088 | | 1979 | 7,777 | | 1978 | 7,446 | | 1977 | 7,103 | | 1976 | 6,785 | | 1975 | 6,520 | | 1974 | 6,308 | | 1973 | 6,156 | | 1972 | 6,061 | | 1971 | 5,981 | | 1970 | 5,885 | | 1969 | 5,776 | | 1968 | 5,648 | | 1967 | 5,496 | | 1966 | 5,343 | | 1965 | 5,200 | | 1964 | 5,062 | | 1963 | 4,921 | | 1962 | 4,777 | | 1961 | 4,630 | | 1960 | 4,472 |
|