| Year | Value | | 2022 | 23,478 | | 2021 | 23,548 | | 2020 | 23,707 | | 2019 | 23,506 | | 2018 | 22,998 | | 2017 | 22,434 | | 2016 | 21,721 | | 2015 | 21,006 | | 2014 | 20,331 | | 2013 | 19,687 | | 2012 | 19,058 | | 2011 | 18,456 | | 2010 | 17,843 | | 2009 | 17,245 | | 2008 | 16,634 | | 2007 | 16,030 | | 2006 | 15,504 | | 2005 | 14,987 | | 2004 | 14,439 | | 2003 | 13,791 | | 2002 | 13,140 | | 2001 | 12,551 | | 2000 | 12,039 | | 1999 | 11,662 | | 1998 | 11,299 | | 1997 | 10,937 | | 1996 | 10,611 | | 1995 | 10,120 | | 1994 | 9,615 | | 1993 | 9,234 | | 1992 | 8,860 | | 1991 | 9,248 | | 1990 | 9,623 | | 1989 | 9,298 | | 1988 | 8,985 | | 1987 | 8,678 | | 1986 | 8,386 | | 1985 | 8,103 | | 1984 | 7,828 | | 1983 | 7,559 | | 1982 | 7,299 | | 1981 | 7,057 | | 1980 | 6,837 | | 1979 | 6,631 | | 1978 | 6,444 | | 1977 | 6,276 | | 1976 | 6,121 | | 1975 | 5,975 | | 1974 | 5,840 | | 1973 | 5,719 | | 1972 | 5,607 | | 1971 | 5,500 | | 1970 | 5,401 | | 1969 | 5,309 | | 1968 | 5,221 | | 1967 | 5,143 | | 1966 | 5,074 | | 1965 | 5,013 | | 1964 | 4,960 | | 1963 | 4,920 | | 1962 | 4,887 | | 1961 | 4,851 | | 1960 | 4,813 |
|