| Year | Value | | 2022 | 24,497 | | 2021 | 24,115 | | 2020 | 23,715 | | 2019 | 23,310 | | 2018 | 22,895 | | 2017 | 22,462 | | 2016 | 22,001 | | 2015 | 21,513 | | 2014 | 21,011 | | 2013 | 20,494 | | 2012 | 19,958 | | 2011 | 19,407 | | 2010 | 18,854 | | 2009 | 18,328 | | 2008 | 17,843 | | 2007 | 17,393 | | 2006 | 16,983 | | 2005 | 16,607 | | 2004 | 16,193 | | 2003 | 15,689 | | 2002 | 15,127 | | 2001 | 14,523 | | 2000 | 13,876 | | 1999 | 13,267 | | 1998 | 12,730 | | 1997 | 12,209 | | 1996 | 11,697 | | 1995 | 11,197 | | 1994 | 10,701 | | 1993 | 10,230 | | 1992 | 9,780 | | 1991 | 9,322 | | 1990 | 8,874 | | 1989 | 8,478 | | 1988 | 8,129 | | 1987 | 7,823 | | 1986 | 7,586 | | 1985 | 7,400 | | 1984 | 7,232 | | 1983 | 7,060 | | 1982 | 6,871 | | 1981 | 6,672 | | 1980 | 6,470 | | 1979 | 6,256 | | 1978 | 6,026 | | 1977 | 5,795 | | 1976 | 5,564 | | 1975 | 5,361 | | 1974 | 5,217 | | 1973 | 5,122 | | 1972 | 5,062 | | 1971 | 5,029 | | 1970 | 4,985 | | 1969 | 4,904 | | 1968 | 4,799 | | 1967 | 4,686 | | 1966 | 4,571 | | 1965 | 4,457 | | 1964 | 4,346 | | 1963 | 4,239 | | 1962 | 4,139 | | 1961 | 4,042 | | 1960 | 3,948 |
|