| Year | Value | | 2022 | 9,770 | | 2021 | 9,966 | | 2020 | 10,203 | | 2019 | 10,475 | | 2018 | 10,618 | | 2017 | 10,610 | | 2016 | 10,645 | | 2015 | 10,785 | | 2014 | 10,884 | | 2013 | 10,741 | | 2012 | 10,571 | | 2011 | 10,459 | | 2010 | 10,396 | | 2009 | 10,362 | | 2008 | 10,327 | | 2007 | 10,261 | | 2006 | 10,126 | | 2005 | 10,036 | | 2004 | 9,919 | | 2003 | 9,674 | | 2002 | 9,408 | | 2001 | 9,158 | | 2000 | 8,989 | | 1999 | 8,880 | | 1998 | 8,810 | | 1997 | 8,804 | | 1996 | 8,876 | | 1995 | 9,012 | | 1994 | 9,138 | | 1993 | 9,210 | | 1992 | 9,240 | | 1991 | 9,199 | | 1990 | 9,077 | | 1989 | 8,975 | | 1988 | 8,876 | | 1987 | 8,683 | | 1986 | 8,449 | | 1985 | 8,202 | | 1984 | 7,938 | | 1983 | 7,672 | | 1982 | 7,415 | | 1981 | 7,166 | | 1980 | 6,948 | | 1979 | 6,788 | | 1978 | 6,662 | | 1977 | 6,511 | | 1976 | 6,321 | | 1975 | 6,159 | | 1974 | 6,022 | | 1973 | 5,853 | | 1972 | 5,675 | | 1971 | 5,393 | | 1970 | 5,011 | | 1969 | 4,652 | | 1968 | 4,452 | | 1967 | 4,309 | | 1966 | 4,162 | | 1965 | 4,008 | | 1964 | 3,873 | | 1963 | 3,736 | | 1962 | 3,611 | | 1961 | 3,515 | | 1960 | 3,450 |
|