| Year | Value | | 2022 | 6,568 | | 2021 | 6,492 | | 2020 | 6,433 | | 2019 | 6,379 | | 2018 | 6,329 | | 2017 | 6,281 | | 2016 | 6,241 | | 2015 | 6,214 | | 2014 | 6,204 | | 2013 | 6,212 | | 2012 | 6,235 | | 2011 | 6,259 | | 2010 | 6,264 | | 2009 | 6,218 | | 2008 | 6,120 | | 2007 | 5,989 | | 2006 | 5,814 | | 2005 | 5,609 | | 2004 | 5,393 | | 2003 | 5,170 | | 2002 | 4,918 | | 2001 | 4,637 | | 2000 | 4,371 | | 1999 | 4,133 | | 1998 | 3,924 | | 1997 | 3,753 | | 1996 | 3,611 | | 1995 | 3,473 | | 1994 | 3,338 | | 1993 | 3,217 | | 1992 | 3,105 | | 1991 | 2,989 | | 1990 | 2,869 | | 1989 | 2,750 | | 1988 | 2,632 | | 1987 | 2,513 | | 1986 | 2,395 | | 1985 | 2,282 | | 1984 | 2,177 | | 1983 | 2,075 | | 1982 | 1,979 | | 1981 | 1,891 | | 1980 | 1,815 | | 1979 | 1,756 | | 1978 | 1,706 | | 1977 | 1,666 | | 1976 | 1,639 | | 1975 | 1,624 | | 1974 | 1,613 | | 1973 | 1,614 | | 1972 | 1,628 | | 1971 | 1,650 | | 1970 | 1,677 | | 1969 | 1,709 | | 1968 | 1,745 | | 1967 | 1,776 | | 1966 | 1,804 | | 1965 | 1,828 | | 1964 | 1,848 | | 1963 | 1,865 | | 1962 | 1,879 | | 1961 | 1,888 | | 1960 | 1,892 |
|